Week 2- OR Safety & Opioids Flashcards
The synthesis of heroin in 1874 was based on the empirical finding that boiling _________ caused the replacement of the two groups: __________ by __________
Morphine; -OH by -OCOH3
7 uses of opioids
- preoperative meds
- anesthesia
- Induction
- intraop pain control
- post op pain control
- spinal/epidural anesthesia
- OB
Normal fentanyl dose
50-100 mcg
Common opioid added to epidurals and spinal
Duramorph
Name the piperidines
-fentanyl
-sufentanil
-alfentanil
- remifentanil
Piperidine opioids are
Synthetic
Synthetic opioid commonly used for eye blocks due to its fast on/off onset/DOA
Alfentanil
What side effect may be seen after intraoperative morphine use in the postoperative area
Itching
Dilaudid:
Acts on _________ and is an __________
Comes in a ____________ vial
Typically it is ____________
Common name for Dilaudid is _________
Mu, agonist
10 mg/cc
Diluted
Hydromorphone hydrochloride
What type of agonist/antagonist is Ketamine and on what receptor does it act
NMDA receptor antagonist, also works on opioid receptors
Clinical effects of acting on mu-1
- supraspinal analgesia
- bradycardia
- Sedation
- pruritis
- N/V
Examples of mu-1 agonists
Morphine and meperidine
Clincal effects of acting on mu-2
- respiratory depression
- euphoria
- physical dependence
- pruritis
- constipation
Clincial effects of acting on the K (kappa) receptor
- Spinal analgesia
- respiratory depression
- sedation
- miosis
Clinical effects of acting on the delta receptor
- spinal analgesia
- respiratory depression
Example agonists of the mu-2 receptors
Morphine and meperidine
Example agonists of the kappa receptors
Fentanyl, morphine, and nalbuphine
Example agonists of delta receptors
Oxycodone, B-endorphine, Leu-enkaphalin
Are piperidines lipophilic or lipophobic
Lipophilic
Where are fentanyl, alfentanil, and sufentanil metabolized and what enzyme catalyzes these breakdowns
Liver; cytochrome P450 enzyme system
How much more potent is fentanyl than morphine
~ 100 x more potent
Why is fentanyl typically used in anesthesia
To decrease CV response to noxious stimuli from laryngoscopy, intubation, skin incisions, and surgical stress
Administering fentanyl can decrease inhalational anesthetic requirements by 50% by administered _________________ IV fentanyl
1.5-3 mcg/kg
The two most pain provoking things that occur in surgery
Intubation and skin incision
T or F: Fentanyl is considered an “additive drug”
T
Sufentanil is a ___________derivative of fentanyl and is _________ more potent than fentanyl
Thienyl; 10 X
What meds lipophilicity is 2x greater than fentanyl’s
Sufentanil
Is sufentanil metabolized to inactive or active compounds
Both
Where is sufentanil metabolized
Liver
Metabolizes remifentanil
Blood and tissue nonspecific esterases
What type of chemical side chain on remifentanil affects its metabolization
Methyl ester
CSHL of remifentanil
2 minutes
Most rapidly acting opioid available
Remifentanil
Clearance of remifentanil
3-5 L/min
Is remifentanil metabolized in liver? Why or why not
No. It’s clearance exceeds liver blood flow affirming its extrahepatic clearance
Why is remifentanil usually a continuous infusion
It’s plasma level decreases by 50% in ~ 40 seconds
Active metabolite of ________ can cause seizures
Meperidine
Does morphine cross BBB quickly or slowly? Why?
Slowly due to low lipophilicity
Goal for patient in preoperative timeframe
To RELAX then not to sedate them…. Yet
How long to the onset of action for dilaudid
10- 15 mins
Who tends to have higher effects from narcotics?
Neonates, elderly, patient with OSA
What causes an increase in biliary pressure
Contraction of the sphincter of Oddi as a result of opioid use
Can you reverse the contraction of of the sphincter of Oddi?
Yes with naloxone or glucagon
How do opioids cause N/V
- Stimulates the chemoreceptor trigger zone in the postrema of the brain stem.
- direct effects on the GI tract,
- increased sensitivity of the vestibular system
What can be given to descrease incidence of coughing during an EGD and why
Fentanyl … acts on medullary cough centers
What is wooden chest syndrome
After giving narcotics, you can’t ventilate
Risk factors for wooden (rigid) chest syndrome
- high cumulative doses
- extremes of age
- concamitant use of meds that modify dopamine levels
- rapid IV admin
- critical illness
- lipophilic opioids
The duration of effect of narcan is
15-45 minutes
Administration of narcan
40 mcg every 1-2 minutes until good RR/ventilation
How to dilute narcan
4 mg per vial, 1 vial diluted in 9 cc NS = 40 mcg/cc
Adverse effects of reversing the effects of narcotics with naloxone
- sudden pain
- pulm edema
- cardiac arrhthymias
- HTN
- Seizures
- cardiac arrest
What type of receptor family are opioids acting on
G-protein coupled receptor family
When opioid receptors are signaled, what happens to the channels
K+ and Ca2+ activation
In reference to the function of an opioid receptor, what is the cascade of the signaling pathway
- Inhibit adenyl cyclase & decrease cyclic AMP
- Activation of Ca2+ and K+ channels
- Activation of mitogen activated protein kinase/extra cellular signal/regulates kinase, protein kinase C, and P13 KK/Akt
What two things can antagonism of NMDA receptors lead to
-reduce opioid tolerance
- reduce opioid induced hyperalgesia and hypersensitivity (in chronic disease states)
What does NMDA stand for
N-methyl-D-Aspartate
Explain the receptors ketamine works on
NMDA antagonist causing anesthetic properties and analgesic effects due to MOR activation
What is nociception
Neural process of encoding and processing of noxious stimuli that can cause tissue damage
3 examples of analgesia driven by endogenous opioid system
- Stress induced
- Placebo induced
- Condition pain modulation (CPM)
What is conditioned pain modulation (CPM)
Pain from noxious stimuli applied to one part of body is decreased by application of second remote noxious stimuli
What causes CPM
Activation of descending inhibitory pathways by higher brain centers
Opioids are involved in peripheral analgesia in what ways
Act directly on sensory neurons (A and C fibers) to inhibit pain transmission
opioid receptors found in (name 2)
Neurons & immune cells (leukocytes)
OIH activation mechanisms (name 3)
- Central glutaminergic systems
- Central nitric oxide production
- Facilitation of descending pronociceptive systems
Postoperative patients who received _________ during surgery may have higher incidence of OIH. How can you prevent it
Remifentanil
- administer morphine (0.1-0.25 mg/kg) 45-60 minutes before surgery ends OR can add low dose ketamine (10-30 mg/hr)
Semisynthetic exogenous opioids
Dilaudid
Buprenorphine
Oxycodone
Codeine
Full opioid agonist of the MOR
Morphine, piperidines, and methadone
Opioids that are partial agonist
Buprenorphine
Opioid antagonists
Naloxone and naltrexone
Explain opioid metabolism that may occur in GI, brain, kidney
Extraction of parent drug/metabolites via kidney and/or biliary tract into the gut where some opioids reuptake the compound in the blood stream. Examples are morphine and buprenorphine
Enzyme metabolizing morphine in phase II reaction
UGT2B7
Active metabolite of morphine? What percentage is converted to active form? What should you be cautious of?
M6G
5-10%
Patient with decreased renal function
Transport protein that moves M3G and M6G to bloodstream? To bile ducts?
MRP3 bloodstream
MRP2 bile duct
Opioids that readily cross BBB
Pipieridines
The most important metabolic pathway of naloxone is via ________ and the metabolite is ________
Glucuronidation
Inactive naloxone-3-glucuronide
The opioid affect sites for analgesia, sedation, constipation, and respiratory depression
CNS- analgesia, sedation, respiratory depression
GI- constipation
Explain how opioids affect respiratory rate
Reduced TV due to decreases input to brain stem
If given slowly, respiratory neuron depression coincides with increased arterial CO2 accumulation which stiulates peripheral ad central chemoreceptors which offsets decrease in tidal volume and reduced RR
Opioids can increase collapsibility of upper airways d/t suppression of neurons in brain stem or from loss of muscle tone related to sedation
Naloxone onset
6.5 minutes
Special considerations when administering naloxone to reverse buprenorphine
Consider naloxone infusion d/t long actin buprenorphine and short acting naloxone
What area is triggered that could cause PONV following opioids
Chemoreceptor trigger zone (CTZ) which is near vagal nerve, and vestibular organs
Treatment for PONV from opioids
Dopamine antagonist (droperidol)
5HT-antagonist (Zofran)
Corticosteroids
What do opioids do to GI tract
- Inhibit intestinal and pancreatic secretion,
- increase bowel tone,
- decrease intestinal propulsive activity
How to treat opioid induced bladder dysfunction
Opioid antagonist
Remifentanil PCA for labor pain
- used when epidural contrainidcated
- bolus dose 30 mcg with a 3 minute lockout
WHO surgical checklist only applies to what people in the OR
it applies to the WHOLE OR
when are surgical checklists performed
- prior to induction of ANE
- pre-op
- prior to skin incision
- before pt leaves OR
rate of anesthetic drug errors
1 in 133
3 most common meds involved in medication errors
-opiates
- muscle relaxants
- antibiotics
from who’s study did the WHO surgical checklist originate and when
2009- Dr. Gawande and his group from Harvard
in summary: why are we learning the entirety of the ANE machine
the study where they created 5 leaks in the machine
- ave number faults found= 2.2
- 7.3% found no faults
- only 3.4% found all five
greater emphasis on fundamentals of ANE machine
Causes of failure to deliver O2 to the alveoli- Upstream from workstation (6)
- liquid O2 reservoir empty or filled with hypoxic gas (nitrogen)
- crossed hospital pipelines
- crossed hoses or adapters in OR
- closed pipeline valves
- disconnected O2 hose
- failure to back up hospital O2 reserve
Causes of failure to deliver O2 to the alveoli- within the machine or circuit (12)
- cylinder filled with hypoxic gas
- empty O2 cylinder
- incorrect cylinder on O2 yoke
- crossed pipes with machine
- closed O2 cylinder valve
- O2 flowmeter off
- failure of the proportioning system
- O2 leak within the machine or flowmeter
- incompetent or absent circuit unidirectional valves
- breathing circuit leak
- closed system ANE w/ inadequate fresh O2 supply
- inadequate ventilation
3 complications of failure to deliver O2 to alveoli
- hypoxia
- hypocarbia
- hypercarbia
what would cause you to suspect the substance being delivered isn’t actually O2 and what should you do
the oxygen analyzer alarm
disconnect pipeline and open O2 tank on back of machine for O2 delivery
normal OR temperature
68-73 degrees
in what situations should the OR be kept warmer
- burns
- large surface area exposed
- pediatric patients
- trauma
usual humidity level of OR
&
ideal humidity level of OR
30-60%
50-55%
what happens if the OR humidity is too high
damp or moist supplies increase the incidence of contamination
what happens if the OR humidity is too low
- facilitate airborne motility of particulate matter, vector for infection
- increase incidence of static changes
what does WHO stand for
World Health Organization
what does NIOSH stand for
National Institute for Occupational Safety and Health
what does NIOSH do
ensure employees work in safe and healthy environment
what are NIOSH recommended exposure limits (REM) for halogenated agents
2 ppm for halogenated agents
what are NIOSH recommended exposure limits (REM) for halogenated agents when used in combination with N2O
0.5 ppm for halogentaed and 25 ppm for N2O when used in combination
what are NIOSH recommended exposure limits (REM) for nitrous oxide alone
25 ppm for N2O alone
potential leak sources of anesthesia machine
- tank valves
- high/low pressure machine connections
- connection in breathing circuit
- defects in rubber and plastic tubing, hoses, reservoir bags, vet bellows, and y-connector
potential OR contamination sources
- spills while filling vaporizers, flushing circuits
- loose fitting masks
- uncuffed ETT
- malfunction/leak in the scavenging system
- cryosurgery, CV bypass units, PACU
what can decrease contamination of the surgical site and how is it done
high rate of OR airflow
blend 80% recirculated air with fresh air
T or F: ventilation systems in OR are not suitable for WAGD
True
is OR pressure + or - and why
slightly +
** drive away gases that escape scavenging
** Fresh Air flow moves/enters from the ceiling to the floor
what does NFPA stand for
National Fire Protection Agency
NFPA recommendation for air exchange and why
25 air volume exchanges/ hour from OUTSIDE.. not from hospital air
decrease the risk of stagnation and bacterial growth
why halogenated lights in OR
less fatiguing on the eyes
- light is given off as brightness rather than heat to protects delicate tissues
normal OR noise levels
70-80 decibels (dB) with frequent sound peaks
why is anesthesia compared to flying a plane
pre-flight planning= pre-anesthetic assessment and plan
take-off= induction
autopilot= maintenance
landing= extubation
taxi to terminal= PACU
7 principles of crew resource management
- Communication
- Assertiveness
- Situational awareness
- Analysis
- leadership
- adaptability/flexibility
- decision making
Acronym: Crew Resource Management wants a C.A. SALAD
patient safety concerns of anesthesia practitioners
- distractions
- production pressures
- communication (handoffs)
- med safety
- postop respiratory and NMB monitoring
the triad necessary for OR fire and examples of each
O- oxidizer (oxygen, nitrous oxide)
F- fuel (ETT, drapes, surgical supplies)
I- ignition source (cautery, laser)
O2 content < than _______% decreases fire risk
30
T or F: a major cause of fire in the OR is failing to allow the alcohol-based skin prep to dry for 90 seconds
F- 3 minutes!
steps to perform if you have an airway fire
- pull tube
- turn off all gas
- pour fluid down airway
steps to avoid airway/OR fire
- prevent triad
- O2 < 30%
- wet gauze around area
- decrease O2 during cauterization
- turning down the O2 2-3 minutes before the surgeon need cautery
- let alcohol-based solutions dry
- communicate
estimated # of surgical fires per year in US
600
T or F: all surgeries have a risk of fire
T
surgeries to what body area account for 65% of surgical fires
head, face, neck, and upper chest
examples (3) of cases where you may need to use O2 with an awake patient
- cartoid artery surgery
- neurosurgery
- some pacemaker implantations
what does APSF stand for
anesthesia patient safety foundation
what is Ohm’s law
E (electromotive forces)= I (Current) X R (Resistance)
what are the units for E= I X R
E= volts
I= amperes
R= ohms
in Ohms law E= I X R, what is the current representing
flow of electrons
what is Ohms law related to in the body
BP!
BP = CO X SVR
BP ~ voltage, CO = current and SVR = resistence
two types of defibrillators
DC - direct current (Monophasic)
AC- alternating current (Biphasic)
any substance that permits flow of electrons
conductor
opposes flow of electrons
insulator
electron flow is always in the same direction
direct current
electron flow that reverses directions at regular interncval
alternating current
sum of forces that opposes electron movement in an AC current
impedene
is Ohms law usually applied to AC or DC currents?
DC
3 ways electricity can cause morbidity/mortality
- electrocution
- burns
- ignition of flammable material, causing a fire or explosion
electrocution effects depend on what 4 factors
- the amount/current of electricity
- where the current flows and its density
- type of current
- current durations
what voltage and Hz do utility companies supply to house
120 V
Frequency of 60 Hz
typical power cords has two conductors
- one hot that carries current to the impedance
- one neutral and returns current to the source
is a house a grounded or ungrounded system
Grounded to EaRtH
when does electric shock occur
when a person becomes part of/completes the circuit
how does electrical injury occur (name 2)
- release of thermal energy= burns
- disruption of nervous, muscular, and cardiac function (Vfib)
the extent of injury following electrical shock is a function of the __________ and _________
current (amperes) and duration of current flow
maximum harmless current intensity
(Macroshock)
5 mA
“Let-go” current above which sustained muscle contraction occurs
(Macroshock)
10-20 mA
current at which vfib will start but respiratory center remains intact
100-300 mA
current at which there is sustained myocardial contraction, followed by normal heart rhythm; temporary respiratory paralysis, burns if current density is high
6000 mA or 6 A
define macroshock
a large amount of current applied to the external surface of the body which can cause harm or death
define microshock
relatively small current applied directly to the myocardium in susceptible patients
recommended maximum leakage current vs VFIB current for microshock in pacemakers
10 uA (0.01 mA) vs 100 uA (0.1mA)
most common cause of macroshock
faulty or damaged wires in electrical equipment
which is more common… microshock or macroshock
macroshock
describe the grounding of equipment in the OR
electrical power is ungrounded BUT the equipment is grounded
Electricity entering the OR is NOT grounded, it is electrically ____________
isolated
what is an isolation transformer
isolates the OR power supply from ground
where does the line isolation monitor (LIM) take effect
with the first fault, sets off the LIM and OR becomes grounded. after the second fault, the circuit is complete and electrical shock occurs
features of the isolated power system
- provide protection from macroshock
- faulty equipment will not usually trip circuit breakers (life support systems)
will an individual contacting one side of the isolated power system and standing on the ground be shocked
no
what does a line isolation monitor do
continuously monitors the integrity of an isolated power system
when is a line isolation monitor alarm activated
2-5 mA
** Alarm is activated if an unacceptably high current flow to ground becomes possible
T or F: line isolation monitor does not provide complete protection from electrocution
T
what does 2 mA or 3 mA on a LIM tell you
indicates how much current WOULD flow in the event of a second fault
** the reading on the LIM meter does not mean that the current is actually flowing; rather indicates how much would flow in the event of a second fault.
LIM is triggered…. what are the next steps (5 of them)
- check the gauge to see if a real alarm
- if gauge > 5 mA, there is likely faulty equipment
- identify faulty equipment by unplugging each piece of equipment (start with the once connected last).
- if the faulty piece is not needed, then remove it
- if the faulty piece is needed, can be used, but do NOT plug in new additional equipment
what is longest piece of plug and why
the ground portion to prevent electrocutionnnnn
- first to enter the receptacle
why would ground fault circuit interrupters be bad in the OR
it would interrupt life-saving monitors without warning.
what are electrosurgical units (ESU) used for
to cut or coagulate tissue using high radiofrequency electrical energy
ESU can cause electrical interference with what?
your equipment like ECG, CO, Pulse OX
what type of ESU system has electricty that travels from the probe thru the patient and then exits vie the return pad to complete the circuit and requires a return pad
monopolar ESU
what type of ESU system has electricity travel from the active electrode, through the local tissue, and then exits the patient thru the return electrode
bipolar ESU
when would you typically see bipolar ESU
surgery you dont need a lot of energy– eye, neuro
the use of what type of ESU may cause electrical interference in an AICD
unipolar ESU
**AICD could interpret it as V.Tach and trigger defibrillation.
T or F: MAcroshock occurs when a current as small as 1 uA flows through a person
F
radiation-sensitive organs
eyes, thyroid, gonads, blood, bone marrow, and the fetus
what radiation level should be monitored
Above >40 REM
** will need film badge
the basic principle of radiation safety
ALARP= As Low As Reasonably Possible
T/F: Anesthesia has their own scavenging system and the OR has their own scavenging system.
True
A _______ rate of the operating room airflow ________ contamination of the surgical site
High ; decreases
** OR doesn’t like stagnant air
Air return in the OR is handled at or near the ______ level.
Floor
Human ear drum breaks instantly when exposed to sounds louder than:
160 decibel (dB).
Cases that involve stripping of the pleural or resection of the pulmonary blobs, or tracheobronchopleural fistula, can easily result in high concentrations of __________ in the thoracic cavity when the lung is reinflated due to gas leakage.
Oxygen
**fire hazard
If surgeon needs the lung inflated, then applying ________ with air instead of oxygen will greatly reduced the risk of a fire.
CPAP
Two major ignition sources for OR fires are the:
ESU & the laser
Instead of an electronic scalpel, a _______ or __________ scalpel should be used to prevent fires.
Bipolar/Harmonic
Safe during external and internal exposure for fires on the patient in the OR
Readily dissipates, nontoxic, least likely to cause thermal injury
CO2 fire-extinguisher
** use it if fire in OR w/ patient
This extinguisher contains water but can be a problem around electrical equipment.
“ A” rated extinguisher
Water mist are good but requires time, enough volume with multiple mist attempts.
“AC” rated extinguisher
In Ohm’s law. Voltage is:
The driving force
In Ohms law. Impedance is :
Resistance
Electrical power (P) is measured in
Watts (W)
Energy produced by a defibrillator is measured in
watt-seconds or joules.
An insulator has ________ impedance to electron flow.
A conductor has _______ impedance to electron flow.
High
Low
T/F it takes as much as 3X DC as to AC to cause V.fib
True
Refers to LARGE amounts of current flowing through a person, which can cause harm or death
Macroshock
Refers to very small amounts of current and applies ONLY to the electrically susceptible patient
Microshock
(Ex. Individual w/external conduit that is in DIRECT CONTACT w/ the heart - pacing wire, CVC and PA cath).
Biggest difference between macroshock and microshock
LOCATION.
The severity of an electrical shock is determined by the amount of _________and the duration of the flow. NOT ________.
Current
**NOT VOLTAGE.
Electric shock is produced by _________, not _______.
Current ; voltage
What color?
Hot wire =
Neutral wire =
Ground wire=
Black
White
Green
For a shock, contact with the electrical circuit at two points with a _________ source that causes the current to flow through a person
VOLTAGE
Threshold of perception
(Macroshock)
1 mA
Pain, possible fainting, mechanical injury;
( heart and respiratory functions continue)
Macroshock
50 mA
Line isolation system contains:
- a line isolation transformer
- and line isolation monitor
T/F: LIM alarm does not necessarily mean that there is hazardous situation, but rather that the system is no longer totally isolated from ground
True
Ground fault circuit interrupter:
Monitors for equality of current flow
* can detect currents at 5 mA.
*Interrupts current flow before shock occurs
When GFCIs are used in an OR, only ______ outlet is protected by each GFCI. The should never be __________, so that one GFCI protects multiple outlets.
ONE ; “daisy-chaine”
It is essential that the return plate has the appropriate amount of ________ and an intact _______.
Conductive gel ; return wire
** pad to no be placed over bony prominences or metal
What is Methyl methacrylate
Blue cement used in total hips/ total knees
***Causes headaches, N/V, congenital defects.
1 occupational hazard in anesthesia
Substance Abuse
Radiation induces ________
Cataracts
