Title: Anesthesia
1Anesthesia
2Anesthesia
- From Greek anaisthesis means not sensation
- Listed in Baileys English Dictionary 1721.
- When the effect of ether was discoveredanesthesia
used as a name for the new phenomenon.
3Basic Principles of Anesthesia
- Anesthesia defined as the abolition of sensation
- Analgesia defined as the abolition of pain
- Triad of General Anesthesia
- need for unconsciousness
- need for analgesia
- need for muscle relaxation
4History of Anesthesia
5History of Anesthesia
- Ether synthesized in 1540 by Cordus
- Ether used as anesthetic in 1842 by Dr. Crawford
W. Long - Ether publicized as anesthetic in 1846 by Dr.
William Morton - Chloroform used as anesthetic in 1853 by Dr. John
Snow
6History of Anesthesia
- Endotracheal tube discovered in 1878
- Local anesthesia with cocaine in 1885
- Thiopental first used in 1934
- Curare first used in 1942 - opened the Age of
Anesthesia
7- Anesthesiologists care for the surgical patient
in the preoperative, intraoperative, and
postoperative period . Important patient care
decisions reflect the preoperative evaluation,
creating the anesthesia plan, preparing the
operating room, and managing the intraoperative
anesthetic.
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9Preoperative Evaluation
- The goals of preoperative evaluation include
assessing the risk of coexisting diseases,
modifying risks, addressing patients' concerns,
and discussing options for anesthesia care.
10- What is the indication for the proposed surgery?
It is elective or an emergency? - The indication for surgery may have particular
anesthetic implications. For example, a patient
requiring esophageal fundoplication will likely
have severe gastroesophageal reflux disease,
which may require modification of the anesthesia
plan (e.g., preoperative non particulate antacid,
intraoperative rapid sequence induction of
anesthesia).
11- What are the inherent risk of this surgery?
- Surgical procedures have different inherent
risks. For example, a patient undergoing coronary
artery bypass graft has a significant risk of
problems such as death, stroke, or myocardial
infarction. - A patient undergoing cataract extraction has a
low risk of major organ damage.
12- Does the patient have coexisting medical
problems? Does the surgery or anesthesia care
plan need to be modified because of them?
13- Has the patient had anesthesia before? Were there
- Complication such as difficult airway
management? Does the patient have risk factor for
difficult airway management?
14Creating the Anesthesia Plan
- After the preoperative evaluation, the anesthesia
plan can - be completed. The plan should list drug choices
and doses - in detail, as well as anticipated problems .Many
variations on a given plan may be acceptable, but
the trainee and the supervising anesthesiologist
should agree in advance on the details.
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18Preparing the Operating Room
- After determining the anesthesia plan, the
trainee must prepare the operating room .
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22Anesthesia Providers
- Anesthesiologist ( aphysician with 4 or more
yearsof speciality training in anesthesiology
after medical school) - Certified registered nurse anesthetist (CRNA),
working under the direction and supervision of an
anesthesiologist or a physician - CRNA must have 2 years of training in anesthesia
23Patient Safety
- Patient risk and safety are concerns during
surgery and anesthesia . - Data from a number of studies of death caused by
anesthesia indicate a death rate ranging from 1
per 20,000-35,000. - A fourfoulded decline over the last 30 years even
though surgical procedures are undertaken on
increasingly sicker and much higher risk patients
than in the past. - Awareness of potential problems and constant
vigilance (the process of paying close and
continuous attention) are crucial to good patient
care.
24Preoperative preparation patient evaluation
- Anaesthesiologist
- reviews the patients chart,
- evaluate the laboratory data and diagnostic
studies such as electrocardiogram and chest
x-ray, - verify the surgical procedure,
- examins the patient,
- discuss the options for anesthesia and the
attendant risks and - ordered premedication if appropriate
25The physical status classification
- Developed by the American Society of
Anesthesiologist (ASA) to provide uniform
guidelines for anesthesiologists. - It is an evaluation of anesthetic morbidity and
mortality related to the extent of systemic
diseases, physiological dysfunction, and anatomic
abnormalities. - Intraoperative difficulties occur more frequently
with patients who have a poor physical status
classification.
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27Choice of anesthesia
- The patients understanding and wishes regarding
the type of anesthesia that could be used - The type and duration of the surgical procedure
- The patientss physiologic status and stability
- The presence and severity of coexisting disease
- The patients mental and psychologic status
- The postoperative recovery from various kinds of
anesthesia - Options for management of postoperative pain
- Any particular requiremets of the surgeon
- There is major and minor surgery but only major
anesthesia
28Types of anesthesia careGeneral Anesthesia
- Reversible, unconscious state is characterised by
amnesia (sleep, hypnosis or basal narcosis),
analgesia (freedom from pain) depression of
reflexes, muscle relaxation - Put to sleep
29Types of anesthesia careRegional Anesthesia
- A local anethetic is injected to block or
ansthetize a nerve or nerve fibers - Implies a major nerve block administered by an
anesthesiologist (such as spinal, epidural,
caudal, or major peripheral block)
30Types of anesthesia caremonitered anesthesia care
- Infiltration of the surgical site with a local
anesthesia is performed by the surgeon - The anasthesiologist may supplement the local
anesthesia with intravenous drugs that provide
systemic analgesia and sedation and depress the
response of the patients autonomic nervous system
31Types of anesthesia carelocal anesthesia
- Employed for minor procedures in which the
surgical site is infiltrated with a local
anesthetic such as lidocaine or bupivacaine - A perioperative nurse usually monitors the
patients vital signs - May inject intravenous sedatives or analgesic
drugs
32Premedication
- Purpose to sedate the patient and reduce anxiety
- Classified as sedatives and hypnotics,
tranquilizers, analgesic or narcotics and
anticholinergics - Antiacid or an H2receptor-blockingdrug such as
cimitidine (tagamet) or ranitidine (Zantac) to
decrease gastric acid production and make the
gastric contents less acidic - If aspiration occur this premedication decreases
the resultant pulmonary damage - Given 60-90 minutes before surgery, or may be
given i.v. After the pat. arrives in the surgical
suite - NPO for a minimum of 6 hours before elective
surgery - Not given to elderly people or ambulatory
patients because residual effects of the drugs
are present long after the pat. have been
discharged and gone home
33Perioperative monitoring
- Undergeneral anesthesia monitoring
- Inspired oxygen analyzer(FiO2) which calibrated
to room air and 100 oxygen on a daily basis - Low pressure disconnect alarm, which senses
pressure in the expiratory limb of the patient
circuit - Inspiratory pressure
- Respirometer (these four devices are an integral
part of most modern anesthesia machine - ECG
- BP-automated unit
- Heart rate
- Precordial or esophagel stethoscope
- Temp
34Perioperative monitoring
- Pulse oximeters
- End tidal carbon dioxide (ECO2)
- Peripheral nerve stimulator if muscle relaxants
are used - Foly catheter
- For selected patint with a potential risk of
venous air embolism a doppler probe may placed
over the right atrium - Invasive arterial pressure mesurements, central
venous pressure - Pulmonary artery catheter and continous mixed
venous oxygen saturation measured
35Perioperative monitoring
- For special conditions other monitors as
transesophageal echocardiography - Electroencephalogram
- Cereral or neurological may be used
36Inhalational Anesthetic Agents
- Inhalational anesthesia refers to the delivery of
gases or vapors from the respiratory system to
produce anesthesia - Pharmacokinetics--uptake, distribution, and
elimination from the body - Pharmacodyamics-- MAC value
37Regional Anesthesia
- Defined as a reversible loss of sensation in a
specific area of the body - Spinal anesthesia
- Epidural anesthesia
- IV Regional Blocks
- Peripheral Nerve Blocks
38Spinal Anesthesia
- A local anesthetic agent (lidocaine, tetracaine
or bupivacaine) is injected into the subarachnoid
space - Spinal anesthesia is also known as a subarachnoid
block - Blocks sensory and motor nerves, producing loss
of sensation and temporary paralysis
39Possible Complications of Spinal Anesthesia
- Hypotension
- Post-dural puncture headache (Spinal headache)
caused by leakage of spinal fluid through the
puncture hole in the dura-can be treated by blood
patch - High Spinal- can cause temporary paralysis of
respiratory muscles. Patient will need ventilator
support until block wears off
40Epidural Anesthesia
- Local anesthetic agent is injected through an
intervertebral space into the epidural space. - May be administered as a one-time dose, or as a
continuous epidural, with a catheter inserted
into the epidural space to administer anesthetic
drug
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42Complications of Epidural Anesthesia
- Hypotension
- Inadvertent dural puncture
- Inadvertent injection of anesthetic into the
subarachnoid space
43IV Regional Blocks
- Also known as a Bier Block
- Used on surgery of the upper extremities
- Patient must have an IV inserted in the operative
extremity
44IV Regional Block
- After a pneumatic tourniquet is applied to
extremity, Lidocaine is injected through the IV. - Anesthesia lasts until the tourniquet is deflated
at the end of the case.
45IV Regional Blocks
- IMPORTANT- to prevent an overdose of lidocaine it
is important not to deflate the tourniquet
quickly at the end of the procedure.
46Peripheral Nerve Blocks
- Injection of local anesthetic around a peripheral
nerve - Can be used for anesthesia during surgery or for
post-op pain relief - Examples ankle block for foot surgery,
supraclavicular block for post-op pain control
after shoulder surgery
47Monitored Anesthesia Care (MAC)
- Generally used for short, minor procedures done
under local anesthesia - Anesthesia provider monitors the patient and may
provide supplemental IV sedation if indicated
48Conscious Sedation
- Used for short, minor procedures
- Used in the OR and outlying areas
- (ER, GI Lab, etc)
- Patient is monitored by a nurse and receives
sedation sufficient to cause a depressed level of
consciousness, but not enough to interfere with
patients ability to maintain their airway
49Inhalation Anesthetics
- Nitrous Oxide- can cause expansion of other
gases- use of N20 contraindicated in patients
who have had medical gas instilled in their
eye(s) during retinal detachment repair surgery
50Inhalation Anesthetics
- Cause cerebrovascular dilation and increased
cerebral blood flow - Cause systemic vasodilation and decreased blood
pressure - Post-op NV
- All inhalation anesthetics, except N20, can
trigger malignant hyperthermia in susceptible
patients
51Intravenous Induction/Maintenance Agents
- Propofol (Diprivan)- pain/burning on injection,
can cause bizarre dreams - Pentothal (Sodium Thiopental)- can cause
laryngospasm -
52General Anesthesia
- During induction the room should be as quiet as
possible - The circulator should be available to assist
anesthesia provider during induction emergence - Never move/reposition an intubated patient
without coordinating the move with anesthesia
first
53General Anesthesia
- Laryngospasm may happen in a patient having a
procedure with general anesthesia - When laryngospasm occurs, it is usually during
intubation or emergency - Assist anesthesia provider as needed- call for
anesthesia back-up if necessary
54Difficult Airway Cart
- Anesthesia maintains a Difficult Airway Cart
containing equipment supplies for difficult
intubations - This cart is stored in one of the anesthesia
supply rooms - Page anesthesia tech if the cart is needed for
your room
55Cricoid Pressure or Sellick Maneuver
- Used for patients at risk for aspiration during
induction, due to a full stomach or other
factors such as a history of reflux - Pressure on the cricoid cartilage compresses the
esophagus against the cervical vertebrae and
prevents reflux
56Sellick Maneuver
- Cricoid pressure is maintained, as directed by
anesthesia provider, until the ETT cuff is
inflated
57Regional Anesthesia
- Circulator may need to assist anesthesia provider
with positioning for spinal or epidural
anesthesia. - Patient usually is positioned laterally for
placement of regional anesthesia, but may be
positioned sitting upright.
58The Awake Patient
- Patients undergoing surgery with regional or
local anesthesia, even if sedated, may be aware
of conversation and activity in room - Post sign on door to OR, Patient is Awake so
that staff entering room will be aware that
patient is conscious
59When Patient is Awake
- Limit any discussion of patients medical
condition and prognosis - Avoid discussion of other patients limit
unnecessary conversation-- a sedated patient can
easily misinterpret conversation they overhear