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

1. type of drug preparation
2. dosage
3. route of administration
4. 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

1. enternal
2. parenteral
3. 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

1. prescribed medications
2. 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...

1. trade, brand, or proprietary name
2. generic
3. 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

1. principal action
2. the organ or body system affected
3. physiological action produced
4. therapeutic action

Three main theories have been developed to explain the ways that a drug produces its effect(s)

1. 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
2. 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
3. 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

1. Aqueous - prepared in water
2. Syrup - sweetened aqueous solution
3. Tincture - prepared with alcohol
4. 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

1. patient is unaware of activities
2. after adequate airway is secured the depth and rate of respiration can be controlled and the pulmonary tree is usually protected fro aspiration
3. 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)