Pharmacodynamics
the study of the interaction of drug molecules with the target cells of living tissue
variables in pharmacodynamics
type of drug
dosage
route of administration
patient condition
intentional (beneficial)
undesirable (detrimental)
drug interaction can occur when two substances are prescribed concurrently, causing a modification of the action of one or both drugs. This action can be......
Agonists
an interaction occurs when a drug potentiates or enhances the effect of another substance
synergists and additives
two examples of agonists
Synergistic Agents
produce a stronger or more powerful effect than would be demonstrated if each agent was administered individually. The action of one agent increases the action of the other agent when delivered together. As a result, each agent can be given in a lower, sometimes safer dose
Additive Agents
ones that alter some aspect of the action of the original agent
Antagonists
binds to the agonist's receptor site, preventing the agonist from binding there and causing its desired effect. This results in an absence of the agonist's action, referred to as a agonist's reversal.
Therapeutic Action
action of a medication describes the application or situation for which the medication is used and the timing of the effects commonly associated with a given medication and dosage
Associated with Therapeutic Action:
Indication:
is a listing of the medical conditions that the medication is known to treat. The dosage as well as delivery form may vary accordig to the patients's medical condition, age, weight
Associated with Therapeutic Action:
Contraindications:
are a list of circumstances or medical conditions under which the medication should not be used
Associated with Therapeutic Action:
Onset
the period of time required for the effects of the medication to begin to be demonstrated in the patient
Associated with Therapeutic Action:
Peak Effect
the period of time when the maximum effect(s) of the medicaiton are demonstrated
Associated with Therapeutic Action
Duration
the overall period of time when the effects of a medication are demonstrated
The timing of medication administration will depend on:
the time of onset
peak effect
duration of action
The goal of medication administration
to provide the patient with chemical preparation designed to assist in the treatment of illness or disease
Improper dosages
can have little or no effect, or can be harmful, or even toxic, to the patient
Therapeutic effect:
concentration or dose of a medication used to produce the desired result without producing harmful effects
Side effect:
An expected, undesirable, but tolerable effect of a medication
Adverse effect:
undesirable and potentially harmful effect of a medication that can lead to organ damage or failure
Toxic effect:
an undesirable and unacceptable effect of a medication
ex: growth of cancerous tumors, development of birth defects
Pharmacokinetics
the term used to describe the metabolic processing of a drug within the body. This process involves absorption, distribution, biotransformation, and excretion
Absorption
occurs at the site of administration
Passive transport
where the substance is eventually taken into the bloodstream by the capillaries. The drug is transferred from an area of higher concentration to an area of lower concentration
Requires no energy
*Most drugs are transported in this manner
Active transport
An energy source in the form of a cation, is required to carry the substance from an area of lower concentration to one of higher concentration
Absorption is influenced by several factors
- type of drug preparation
- dosage
- route of administration
- patient's condition
A drug intended for local use
must remain at the site of administration to be effective. The vasoconstrictor epinephrine can be added to a drug preparation to slow absorption
Distribution
involves the transport of a medication within the body once it enters the circulatory system. Medication is distributed to the target cells for action, to the liver for biotransformation, and to the liver or kidneys for elimination
Drug administration routes
- enternal
- parenteral
- topical
Distribution of medication is affected by
rate of aborption
transported not only to the intended target tissue, but also to all parts of the body
is also affected or limited by plasma protein binding, tissue binding, and certain barriers established by the body (blood brain barrier, placental barrier)
Biotransformation
metabolism of a drug most often occurs in the liver, but other tissues may be involved
the main function of the liver in drug metabolism
to break down molecules in preparation for excretion....
The products of metabolic breakdown are called metabolites (smaller, inactive substances)
Excretion
medications are physiologically removed from the target organ or tissue via the circulatory system in either an intact or biotransformed (changed or inactivated) state
Enteral:
through the gastrointestinal tract..
oral or rectal
Parenteral:
other than through the gastrointestinal tract; by injection
intradermal (skin), subcutaneous (fat tissue under the skin), intramuscular, intravenous, intra-articular (joint), intrathecal (subarachnoid space), intracardiac (heart)
Topical:
applied to the skin or mucous membrane to provide a localized or systemic effect
buccal (cheek), sublingual( under the tongue), instillation (in a hollow cavity), inhalation (respiratory tract by gas or aerosol)
Route of administration
method used to deliver the medication into the body....
The most common in the OR are parenteral with intravenous administration being the most common
Medications for use in the United States are required to undergo review and approval
FDA
Drugs are prepared for administration in several different forms
gas, liquid, solution, aqueous, syrup, tincture, elixir, suspension, emulsion, solid, semisolid
two legal drug classification most commonly used
- prescribed medications
- over-the-counter medications
Controlled substances
drugs with a high potential to cause psychological and or physical dependence and abuse
Controlled Substances Act of 1970
designated certain drugs as controlled substances, classifying these substances according to their level of addictiveness and therapeutic potential
Schedule or Class I controlled substances
high abuse potential and no approved medical use
example: heroin, marijuana, LSD
Schedule or Class II controlled substances
high abuse potential and high ability to produce physical and or psychological dependence
Schedule or Class III controlled substances
less potential for abuse than drugs in Schedule II, and there is an approved medical use
Schedule or Class IV controlled substances
preparations containing limited amounts of certain narcotic drugs for drugs to treat coughing and diarrhea
Example: cough syrups with codeine
Prescribed medications
medications that if used inappropriately could cause significant harm to the patient. A prescription is a written order for the preparation and dispensing of a medication
Over-the-Counter medications (OTC)
pharmacologic agents that are prepared in a dosage that are safe to administer without the direction of a physician
Alternative medication
products (dietary supplements, nutritional supplements, herbal medicines, probiotics, vitamins, minerals, and other natural products) that have undergone only limited studies to determine the safety and effectiveness of these therapies. Many of the products are no US FDA approved. They may interact with traditional medication producing side effects. May react with anesthetic drugs, causing serious reactions
STs are responsible for understanding basic info. regarding medications they handle on the sterile field
names, classifications, actions, indications, uses in the surgical setting, and dosages
Names
there are three assigned to each drug...
- trade, brand, or proprietary name
- generic
- chemical name
Trade, brand, proprietary name
assigned to a medication and copyrighted by the manufacturer for marketing purposes. Medication is capitalized followed by a symbol specific to the company
Generic name
nonproprietary name for a drug. Written in all lowercase letters.
This name is advocated in the health care setting to avoid confusion between medication with similar-sounding trade names
Chemical name
precise chemical composition and molecular structure of the medication. Complex and difficult to use
Joint Commission publishes
"look-alike/sound-alike" list of medications
the generic name of the medication given to reduce the potential for medication errors
Drugs are classified according to their
- principal action
- the organ or body system affected
- physiological action produced
- therapeutic action
Three main theories have been developed to explain the ways that a drug produces its effect(s)
- the theory of drug-receptor interaction: states that the active substance in the drug has an affinity for a specific chemical constituent of a cell
- the theory of drug-enzyme interaction: states that a drug may combine with a specific enzyme to inhibit the action of the enzyme or alter the cellular response to the enzyme
- Nonspecific drug interaction: related to a drug that does not act by either of the two previously described methods and is considered nonspecific in its interaction
Indication
a listing of common medical conditions that a particular medication is used to treat
Medication Dose
the amount of medication delivered to the patient in order to achieve the desired therapeutic effect. The dose will depend on several factors: age, weight, medical condition, deliver route, and recommended maximum dosage
STs responsibility for dosage of medications
able to perform medication calculations to determine the amount of medication to be administered as well as to accurately track and document the amount of medication delivered to the patient intraoperatively
Medications used in today's OR
are prepared in the pharmacy and transferred to the sterile field in a ready-to-use form. Emergency situations, medications are prepared in the OR by the surgical team
Forms of Drug Preparation
GAS
oxygen and nitrous oxide
Forms of Drug Preparation
LIQUID
Two primary preparations : solution and suspension
Forms of Drug Preparation
SOLUTION
Drug (solute) is dissolved into a liquid (solvent)
Four ways to prepare a solution
- Aqueous - prepared in water
- Syrup - sweetened aqueous solution
- Tincture - prepared with alcohol
- Elixir - Sweetened alcohol solution
Forms of Drug Preparation
SUSPENSION
Solid particles are suspended in a liquid - particles may settle and must be redistributed by shaking prior to administration
Forms of Drug Preparation
EMULSION
Combination of two liquids that cannot mix - droplets of one liquid are dispersed (suspended) throughout the other
Forms of Drug Preparation
SOLID
Powder is considered a solid form of a drug - it may be in the powdered state, contained within a capsule, or compressed into tablet form - some powders must have liquid added prior to use
Forms of Drug Preparation
SEMISOLID
Creams, foams, gels, lotions, ointments, and suppositories
Example of Drug Names
Trade Name: Marcaine or Sensorcaine
Generic Name: bupivicaine/hydrochloride
Chemical Name: 2-piperidinecarboxamide, 1-butyl-N-(2,6-dimethylphenyl)
Cefotetan disodium (Cefotan)
comes in 1-gram(g) or 2-g powdered form that must be reconstituted.
If given intravenously 1g of this is reconstituted using 10ml of sodium chloride 0.9% for injection, resulting in a concentration of 100mg/ml
Concentration of medication
the ratio of solute to solvent, the two components of a solution
This concentration can vary, depending on the strength of the solute and the amount of solvent added to create a solution
Medications can also come in a concentrated liquid form that may be used in the concentrated form or diluted for use in a less concentrated form
example is heparin sodium. Heparin sodium is available in several concentrations, including 500 units per milliliter, 1,000 units per milliliter, and 10,000 units per milliliter. Normal saline for injection can be added to any of these heparin concentrations to make a dilute concentration.
Cumulative dose
On occasion, several different concentrations of the same medication are used during the same procedure. This dose should be documented
Application
The medication's use in the surgical setting. Consideration should also be given to any contraindications for use such as patient sensitivity/allergy
SOME MEDICATIONS HAVE DIFFERING USES WITHIN THE SURGICAL SETTING.
Lidocaine HCI is commonly used as a local anesthetic; however, lidocaine HCI can also be used as an antiarrhythmic to decrease abnormal heartbeats.
Epinephrine
in concentrations of less than 1:100,000, can be injected as a vasoconstrictor, but in concentrations of 1:1,000, it should only be used topically to prevent serious patient complications, including death.
In order to calculate medication dosages on the sterile field, the surgical technologist needs to understand two basic concepts
concentration
cumulative dose
Calculating concentration
convert the solution into units of medications per one unit of fluid; in other words, solute to solvent.
A : B = C : D
Percentages
typically expressed as a whole number followed by the percent symbol %. This can also be expressed as a decimal.
conversion formula for converting between Fahrenheit and Celsius scales are used as follows:
(F - 32)5/9 = C
(C x 5/9) + 32 = F
Metric system
also also referred to as the international System of Units. Is based on powers or muliples of 10 and the value of numbers is established by the use and placement of a decimal point to indicate whole numbers versus fractions.
apothecary systems
Rarely used in the medical field
based on weight of a grain of wheat
minim= volume grain=weight
The six "Rights" of medication administration
patient, drug, dose, route of administration, time/frequency, and documentation (labeling)
Types of OR medication packaging
ampule: glass (requires top to be broken off - liquid)
vial: plastic or glass (liquid, powder, or compressed powder)
preloaded syringe: liquid meds
tube: metal or plastic (cream, gel, or ointment forms
All drugs must be labeled with what information
***Drug name, lot number, handling/storage precautions, reconstitution instructions, classification, manufacturer,*** strength, ***amount,*** expiration date
***indicates the most important when transferring from the circulator to the sterile field (ST)
***when passing to surgeon you do all of them that are starred except expiration date
***Verification is three times prior to administration
Labels on medication syringes
make sure calibrations for measurement are not covered
The classifications of drugs for FEMALE REPRODUCTIVE TRACT
oxytocics, vasopressin, and immunoglobin
oxytocic drugs
used to induce labor and control uterine hemorrhage associated with pregnancy and childbirth.
ex: pitocin
Vasopressin (Pitressin)
second medication used in gynecologic surgery involving the cervix. (sometimes done prior to prep)
injected around cervix during a vaginal hysterectomy, conization, or uterine fibroid
RhoGam
an immunoglobin, administered to Rh-negative women who are pregnant to prevent sensitization of the maternal immune system when pregnant with an Rh-positive fetus
Orthopedic surgery supplies
antibiotics, hemostatic agents, and steroids.
Hemo. agents:Gelfoam, Avitene, thrombin (Thrombinar) and bone wax
steroids: anti-inflammatory (Decadron) Dexamethasone - short acting corticosteroid
Factors affecting hemostasis
preexisting defects = hemophilia (von Willebrand disease
acquired disorders = liver disesase, anticoagulant therapy, antiplatelet therapy, aplastic anemia, and alcoholic induced liver failure
Bone wax
a sterile mixture applied to the cut edges of bone as a mechanical barrier to seal off oozing blood. Body recognizes it as a foreign body.
used in thoracic surgery when the sternum is split in neurosurgerical procedures when a craniotomy is performed, and for orthopedic (ENT) procedures
Absorbable gelatin sponge - Gelfoam/Gelfilm
composed of collagen, a structural protein found in connective tissues.
May be left in the wound postoperatively, because it will be absorbed by the body in 30 days.
Microfibrillar collagen (Avitene)
assists in activating the coagulation process. It is a powder available in preloaded applicators or powdered dispenser. Absorbed and eliminated from the body.
Oxidized Cellulose - (Surgicel)
products are applied directly to the bleeding surface and held in place until bleeding stops
Silver nitrate
often used to control cervical or nasal bleeding. Applied either in stick form as a caustic pencil or in solutions of .01% to 10%.
cotton swab tip applicator will burn through if you touch it
Epinephrine
potent vasoconstrictor and is often combined with local anesthetic agents or with Gelfoam to aid in local hemostasis. Absorbs rapidly by the body but provides localized hemostasis.
Thrombin
part of the blood-clotting mechanism - an enzyme that results from the activation of prothrombin. Bovine origin is used as a topicla hemostatic. NEVER INJECTED!!!!!
cottonoid sponge may be soaked in it. Should be discarded if not used within several hours, because it looses its potency.
Blood loss (EBL)
monitored intraoperatively by several means to aid the surgeon and anesthesia care provider in assessing the patient's hemodynamic status.
Circulator may weigh sponges removed from the field to provide and estimate contained in the sponge.
Whole Blood
all components of blood - not commonly used
treats trauma-induced hemorrhage
Packed red blood cells (PRBCs)
Red blood cell from 1 unit of whole blood after most of plasma is removed
to restore oxygen-carrying capacity
Fresh-frozen plasma (FFP)
The fluid component of blood containing clotting factors removed from 1 unit of whole blood
Restores clotting factors; 1 unit of FFP is given for every 4 units of PRBCs
Platelets
removed from 1 unit of whole blood
enhances blood's clotting ability - less commonly used
Autotransfusion
involves the use of the patient's own blood that has been processed for reinfusion
*Cell Saver
Optimal balanced anesthesia is achieved when all of the following components are addressed:
hypnosis, anesthesia, amnesia, muscle relaxation, optimal patient positioning, continued hemostasis of vital functions
Hypnosis
results from an altered state of consciousness related to the patient's perception of the surgical environment and procedure
Anesthesia
Freedom from pain is the major focus of anesthesia practice
Amnesia
lack of recall of perioperative events and permit the use of safer, less toxic anesthetic agents and techniques
Muscle relaxation
neuromuscular blocking agents, used in combination with inhalation agents, are capable of producing profound muscle relaxation, facilitating endotracheal intubation and the development of new surgical interventions and techniques
optimal patient positioning
advances in surgical procedures demand advantageous access to the surgical site
Continued homeostasis of vital functions
anesthesia is intentionally capable of inducing a state close to death and requires maintenance of the patient at this level for the duration of the surgical procedure.
This make anesthesia administration the most dangerous component of any surgical intervention
Anesthetic agents are administered in what ways
inhalation agents (gas)
via the use of injectable agents
American Society of Anesthesiologists (ASA)
designed this system for screening patients
Classification of Physical Status - Patient risk status of anesthetic agents
Class 3 physical status classification
A patient with severe systemic disturbance or disease; angina, post-myocardial infarction (MI) poorly controlled hypertension, symptomatic respiratory disease, massive obesity
Class 1 physical status classification
Best situation - A patient without organic, physiological, biochemical, or psychiatric disturbances
Class 6 physical status classification
Worst situation - brain dead patient on life support
Agent inhalation
involves the delivery of gases across the lung's alveolar membrane where the agent enters the vascular system and is transported to the brain crossing the blood-brain barrier, affecting the CNS function.
Agent injection
involves the intravenous administration of medications directly into the bloodstream
Agent instillation
involves the administration of medication into an area such as the rectum
Phases of general anesthesia
induction, maintenance, emergence, recovery
induction phase
altering the patient's consciousness to the unconscious state
the environment (atmosphere) while in the induction phase
The ST should stop setting up the back table and Mayo stand to avoid making noise until the patient is fully unconscious
Maintenance phase
Surgical intervention takes place. Administration is most dynamic during this period.
Emergence phase
occurs as the surgical intervention is being completed
Recovery phase
time period during which the patient returns to the optimum lever of consciousness and well-being
Advantages of general anesthesia
- patient is unaware of activities
- after adequate airway is secured the depth and rate of respiration can be controlled and the pulmonary tree is usually protected fro aspiration
- dosages can be easily titrated to control the depth of anesthesia
Risks of general anesthesia
MANY! the greatest is aspiration during the induction and emergence phases
Required fasting to reduce the risk of aspiration:
2 hours
Clear liquids
Required fasting to reduce the risk of aspiration
4 hours
Breast milk
Required fasting to reduce the risk of aspiration
6 hours
light meal
Required fasting to reduce the risk of aspiration
8 hours
solids (meat, fat)
Cricoid pressure
Sellick's maneuver - application of pressure, is performed to reduce the risk of aspiration
laryngospasm and bronchospasm
reactions demonstrated by the anesthetized patient. A slight trigger of the "gag" reflex results in a spasm or rigidity of the patient and/or anesthesia care provider to move air and waste gases in and out of the lungs
MH (Malignant hyperthermia)
potentially fatal hypermetabolic state of muscle activity resulting from a defect in calcium transportation within the muscle fibers of skeletal muscles. It is characterized by increased production of carbon dioxide, tachycardia, muscle rigidity, and finally, a significant, rapid increase in core body temperature.
More common in males. Triggered by sussinylcholine and halogenated inhalation agents. Is diagnosed either by acute crisis symptoms or by muscle biopsy performed under local anesthesia.
The first sign is unexplained tachycardia
Dantrolene sodium (Dantrium) is the agent administered for treatment
Pseudocholinesterase deficiency syndrome
is a genetically transmitted trait that decreases the amount of acetylcholinesterase during muscle stimulation
Prophylactic treatment includes avoiding the administration of depolarizing neuromuscular blocking agents and notifying the anesthesia care provider of the syndrome prior to future anesthesia administration
Allergic reaction
is the result of histamine release in response to exposure to an allergen, a triggering protein
mild - skin irritation to
severe - anaphylaxis (respiratory distress)
Shock
an abnormal physiological state indicated by the presence of reduced cardiac output, tachycardia, hypotension, and diminished urinary output
cardiac dysrhythmias
abnormal heart rate or rhythm
life-threatening - include ventricular tachycardia and ventricular fibrillation. Treatment includes IV administration of lidocaine HCI. Defibrillation and pacemaker insertion may be necessary
Cardiac arrest
involves the cessation of heart pumping action and blood circulation.
The initial treatment for cardiac arrest is CPR, followed by advanced cardiac life support (ACLS)
Anesthetic agents
divided into three categories:
inhalation agents, intravenous agents, and local/regional agents
The patient is provided supportive oxygen therapy during the use of these agents
Inhalation agents
agents that are inhaled and pass into the bloodstream via the respiratory system. They are delivered to the lungs in a gaseous state, where they cross the alveolar membrane and enter the circulatory system for delivery to the brain. Any exhaled or excess gas in the anesthesia circuit, referred to as waste gas, is captured with a scavenging system for removal from the OR environment, and filtered
Nitrous Oxide
clear, colorless gas with a subtle fruity order and is the only true gas still in use. It interacts with the cellular membrane of the CNS to produce analgesia with some amnesia
Volatile agents
liquids whose potent vapors, when inhaled, produce general anesthesia through CNS depression and decreased electroencephalogram (EEG) activity.
They are delivered from a vaporizer, a component of the anesthesia machine, to the patient via a series of tubing called anesthesia circuit.
Anesthetic inhalation agents
sevoflurane, desflurane, enflurane, halothane, isoflurane
Sevoflurane (Ultane)
odorless inhalation agent that does not cause irritation to the respiratory tract. It has a rapid and smooth onset and recovery, making it an ideal agent for both adult and pediatric. Causes bradycardia, and cardiac dysrhythmias and reduced cardiac output. May produce PONV. Does not cause liver damage. Renal complications.
Trigger for MH. More expensive. Becoming agent of choice for appropriate patients
Desflurane (Suprane)
requires the use of a heated vaporizor
Isoflurane (Forane)
halogenated agent that provides moderately rapid induction and recovery. Enhances the effects of neuromuscular blockade. Increases intracranial pressure
Enflurane (Ethrane) and
halothane (Fluothane)
less commonly used agents
pleasant aroma - rapid acting
the second one is a potent uterine muscle relaxant and should never be used on the pregnant female
IV Intravenous agents
delivered directly into the bloodstream - act quickly
removed by the liver and excreted by the kidneys
IV agents are grouped into:
induction, dissociative, opioids, sedatives/tranquilizers, neuromuscular blocking, antimuscarinic/anticholingergic, and adjunctive
IV induction agents
medications used to permit a rapid transition from a state of consciousness (Stage I) to unconsciousness (State III) by causing the patient to quickly pass through the excitement of delirium state (State II)
do not provide pain relief - only sedation and amnesia
ex: propofol (Diprivan)
Dissociative Agents
interrupt the pathways of the brain. Patients appear wide awake, yet they are unaware of their surroundings.
Ketamine HCI (Ketalar) is the most commonly used (documented cases of "flashbacks" limit this agent's use to children 2-10 years of age
Narcotic antagonists
effect of opioids can be reversed by the administration of naloxone HCI (Narcan), which works by competing for CNS receptor sites, preventing opioid binding Naloxone HCI given IV leads to an abrupt onset of pain, as the opioid previously administered no longer provides pain relief
Benzodiazepines
sedative/tranquilizers used in anesthesia by:
reduce the anxiety and apprehension of the preoperative patient and as an adjunct to general anesthesia to reduce the amount of concentration of other more potent agents.
Sedatives do not produce analgesia (pain relief)
Ex: Diazepam (Valium), Versed (Midazolam) #1 relaxant more potent than Valium, shorter duration memory impairment
Nondepolarizing Agents
agents that work by competing for postsynaptic receptor sites at the neuromuscular junction. This competition prevents acetylcholine from being able to stimulate muscle contraction
Depolarizing Agents
agents work by mimicking a release of acetylcholine across the neuromuscular junction. Agent binds to the postsynaptic receptors, causing muscle contraction to occur, which is followed by a period of muscle fatigue. The contraction/relaxation cycle in the muscle is strong enough to be visible; the action is referred to as fasciculation and the patient may experience postoperative muscle ache because of the strength of the fasciculation.
Ex: succinylcholine (Anectine)
Gastric Acid Management
Histamine (H2) antagonists and antacids are agents used to alter the pH of gastric secretions and reduce gastric volume. They are given during the preoperative or intraoperative period
Antiemetics
agents used to prevent post-operative nausea and vomiting (POVN)
Ex: Zofran used the most, Doperidol (Inapsine)
Ringer's solution
used in the OR: a water based solution for injection that contains essential serum electrolytes in the forms of sodium chloride, potassium chloride, and calcium chloride and is physiologically similar to plasma
Induced hyothermia
involves artificial deliberate lowering of the body's core temp. below normal limits. Four levels of cooling involved.
Light - core body temp. is 98.6 and 89.6 degrees F
Moderate - 89.6 to 78.8 degrees F
Deep - 78.8 an 68 degrees F
Profound - drops below 68 degrees F
Caution with epinephrine usage
patients with hypertension or cardiac disease and its use should be limited during administration of a digital or penile block, for use in tissue with preexisting vascular compromise, and in children because of its vasoconstrictive properties.
Remember: not in the fingers, nose, toes, and penis
Cryoanesthesia
involves the reduction of nerve conduction/transmission by localized cooling. Accomplished with ice or the use of machine to produce cooling action. The reduced skin temperature may be a result of pharmaceutical agent sprayed onto the skin, such as ethyl chloride. The result is a localized "freezing" of the skin and superficial nerve endings, blocking nerve impulse transmission and therefore eliminating pain
MAC
Monitored Anesthetic Care - combination of nerve conduction blockade supplemented with analgesics, sedatives, or amnesics
Bier block
provides anesthesia to the distal portion of the upper extremity by injecting a large volume of low-concentration anesthetic agent (lidocaine) into a vein at a level below a tourniquet.
The limb is then exsanguinated with the use of an Esmarch bandage, and teh proximal cuff of the tourniquet is inflated to a level approximately 100mm Hg above the systolic blood pressure
Spinal block
also referred to as intrathecal block, involves injection of an anesthetic agent into the cerebrospinal fluid within the subarachnoid space between the pia mater and arachnoid mater, resulting in the loss of sensation to the entire body below the level of the diaphragm
Spinal block - factors that effect the influence
patient cooperation, patient position, Agent baricity
Agent baricity - solutions with high specific gravity are referred to as hyperbaric solutions and tend to settle toward gravity. Inversely, a solution with low specific gravity is referred to as hypobaric solution and tends to "float" or move away from gravity. Isobaric solutions are solutions with the same specific gravity as CSF.
Acupuncture - non traditional anesthesia option
involves the intense electrical stimulation of specific body sites to alter the perception of pain at the surgical site by the release of endorphins. While a common principal method of intraoperative pain control in Eastern medicine practices, acupuncture is used as an adjunctive therapy in the United States
Airway Delivery/Maintenance devices
ET (Endotracheal) tubes
are available in many diameters and configurations. Adult and pediatric size tubes include inflatable cuffs (ballooned), permitting the creation of a closed airway system when the cuff is inflated. It is connected to the anesthesia machine by the anesthesia circuit.
placed through the patient's nose or mouth, between vocal cords, and into the trachea to provide a patent airway intraoperatively or during ventilatory support
Airway Delivery/Maintenance devices
Stylet
used to modify the curve of an ET tube or support (stiffen) an ET tube during placement. A stylet is made of malleable metal or stiff plastic and is placed within the lumen of the ET tube. The distal tip should not protrude beyond the end of the ET tube, and the proximal end should be severely bent to prevent accidental retention
BIS monitor
assists anesthesia care providers in monitoring the patient's level of anesthesia during the surgical intervention. A noninvasive sensor is placed on the patient's forehead and attached by a cable to the monitor, which continuously monitors the patients's brain waves, computing them into a number ranging from 0-100. The number correlates with the patient's level of consciousness, with a recording of 100 when the patient is wide awake and under 60 when the patient is unconscious.
Capnography
provides breath-by-breath analysis of expired carbon dioxide (end-tidal CO2)
SARA
The System for Anesthetic and Respiratory Analysis is a monitoring device incorporated into the anesthesia machine and is used to monitor the patient's physiological respiratory and anesthetic gas levels.
SARA monitors these functions
capnography, spirometry, and oxygen analyzer
Vital Signs:
Temperature
is regulated by the hypothalamus, which monitors the processes of heat production and heat loss. When the hypothalamus senses a lowered body temperature, it signals the body to increase heat production through muscle contractions and increased cellular metabolism
Vital Signs:
Respiration
the normal rate is called eupnea and varies with age, emotions, activity level, and medication administration. The normal rate consists of one respiration for every four heartbeats, or a 1:4 ratio
Eupnea
normal breathing - Normal CO2 level feedback to the respiratory center of the brain
Blood pressure
assessed manually, the HCP uses a cuff with a manual inflation device, a sphygmomanometer, and a stethoscope to auscultate for Korotkoff's sounds, which will be heard as a tapping sound that gradually increases in intensity as the cuff is deflated. These sounds take place in five distinct phases, which must be recognized for proper measurement.
Induced hypothermia
involves the artificial, deliberate lowering of the body's core temperature below normal limits
Induced hypothermia is indicated as a adjunctive therapy for what use
open-heart surgery, following cardiopulmonary resuscitation, as a treatment for MH, and during hypertensive crisis, organ transplantation and periods of decreased blood flow to the brain
ex: slush machine
Induced hypotension
involves a controlled decrease of blood pressure during anesthetic administration
ex: amputation
Neuroleptanalgesia
uses high doses of neuroleptics (tranquilizers) and narcotic analgesic agents to induce a state of diminished anxiety, sedation, and amnesia.
The two medications for this purpose:
fentanyl citrate, meperidine HCI
Nerve conduction blockade
commonly referred to as local or regional anesthesia, involves the use of pharmaceutical agents to prevent the transmission of sensory nerve impulses. The agent is absorbed by the nerve sheath, decreasing nerve impulse conduction to a point where sensory impulses are unable to be transmitted.
Nerve plexus block
injection of an anesthetic solution in the tissues surrounding a major nerve plexus
Epidural block
injected into the space above the dura
Spinal block (intrathecal)
injected into the cerebrospinal fluid within the subarachnoid space
Regional anesthesia (AKA block)
agent injected into a specific area of the body.
ex: arm, foot, lower extremities
Local anesthesia
injected at the site of surgical procedure
Amino Amides (Nerve conduction blocking agents)
lidocaine - Xylocaine
mepivacaine - Carbocaine
bupivacaine - Marcaine
etidocaine - Duranest
ropivicaine - Naropin
Amino Esters (Nerve conduction blocking agents)
cocaine - Cocaine
procaine - Novocaine
tetracaine - Pontocaine, Cetacaine
Wydase - hyaluronidase - useful during retrobulbar ocular (eye) block
epinephrine - (vasoconstrictor)
Two adjunctive agents associated with nerve conduction blockade agents that influence the onset and duration of action of these agents
Hypnoanesthesia
the second nontraditional anesthesia option. Useful in altering the patients level of consciousness and awareness of the surgical environment
Laryngeal mask airway (LMA)
a device with an inflated cuff placed into the laryngopharynx through the mouth to form a low-pressure seal around the laryngeal inlet, while providing minimal stimulation to the airway.
This is connected to a tube, exiting the patient's mouth which is connected to the anesthesia circuit for the delivery of inhalation agents.
Pulse
composed of two phases of heart action (systole and diastole) and is assessed by palpation of an artery, usually radial artery
Blood pressure
the force that blood exerts against the walls of the blood vessels as the heart contracts (systole) and relaxes (diastole)
oropharyngeal airways and nasal airways
devices used to provide a passageway around the relaxed tongue, establishing an unobstructed airway for normal respiration
Bair Hugger
a patient-warming device that utilizes warm air blown into a special blanket that is placed over the patient
Various devices to "assist" with patient IV fluid delivery
1. fluid-warming devices
2. rapid infusion pump: device attached to IV line to rapidly deliver large volume of blood or fluid to patient
3. infusion control devices: mechanical devices that regulate delivery of IV fluids and medications (monitoring device delivers controlled manner)
Monitoring devices prior to induction and throughout the perioperative period
electrocardiogram, blood pressure monitor, arterial and venous catheterization, temperature monitors, pulse oximeter, BIS monitor, SARA, stethoscope, Doppler, Peripheral Nerve Stimulator, and Arterial blood gases (ABG)