LAB - L4:T1-T2 (Local and General Anasthetics)

What is anesthesia?

A state of depressed CNS activity.

What are the two types of anesthesia?

General anesthesia and local anesthesia.

What are the goals of general anesthesia?

Analgesia (loss of pain perception), unconsciousness (loss of awareness), and amnesia (inability to recall events).

What factors increase the risk for general anesthesia?

CNS factors, cardiovascular factors, respiratory factors, and renal and hepatic function.

What are CNS factors that may complicate general anesthesia?

Underlying neurological diseases such as epilepsy, stroke, and myasthenia gravis.

What cardiovascular conditions can complicate general anesthesia?

Vascular disease, coronary artery disease, or hypotension.

What respiratory conditions can complicate general anesthesia?

Obstructive pulmonary diseases like asthma and chronic obstructive pulmonary disease.

What is balanced anesthesia?

A combination of several drugs to achieve desired effects rather than using one drug.

What are the stages of general anesthesia?

Stage 1: Analgesia, Stage 2: Excitement, Stage 3: Surgical anesthesia, Stage 4: Medullary paralysis.

What occurs during Stage 1 of general anesthesia?

Loss of pain sensation while the patient remains conscious.

What characterizes Stage 2 of general anesthesia?

Excitement and combative behavior with sympathetic stimulation signs.

What happens in Stage 3 of general anesthesia?

Relaxation of skeletal muscles and loss of eye reflexes; surgery can be performed.

What is Stage 4 of general anesthesia?

Very deep CNS depression with loss of respiratory and vasomotor center stimuli; can lead to death.

What are the phases of general anesthesia administration?

Induction, maintenance, and recovery.

What is induction in general anesthesia?

The period from the beginning of anesthesia until surgical anesthesia is reached.

What is maintenance in general anesthesia?

The period from surgical anesthesia until the procedure is complete.

What is recovery in general anesthesia?

The period from discontinuation of the anesthetic until the patient regains consciousness.

What are common pre-anesthetic medications?

Benzodiazepines, barbiturates, antihistamines, antiemetics, opioids, anticholinergics, and muscle relaxants.

What is the action of barbiturate anesthetics?

They induce rapid anesthesia, which is maintained with inhaled drugs.

What is thiopental used for?

It is widely used for intravenous anesthesia induction but has no analgesic properties.

What is the onset time for thiopental?

Rapid onset of action, usually within 10 to 30 seconds.

What is the recovery time for thiopental?

Ultrashort recovery period of 5 to 8 minutes.

What are the signs of general anesthesia?

Total analgesia, loss of consciousness, memory, and body movement.

What is the role of preoperative medications in general anesthesia?

To facilitate intubation, prevent bradycardia, and decrease secretions.

What is the recovery period for Thiopental?

5 to 8 minutes.

What is the recovery period for Methohexital?

Usually 3 to 4 minutes.

What are common adverse effects of barbiturate anesthetics?

Decreased pulse, hypotension, suppressed respirations, decreased GI activity, nausea, and vomiting.

Name a non-barbiturate anesthetic used for intravenous administration.

Examples include droperidol, etomidate, fospropofol, ketamine, midazolam, and propofol.

What should midazolam be monitored for?

Respiratory depression and CNS suppression.

What adverse effects can droperidol cause during recovery?

Hypotension, chills, hallucinations, drowsiness, and QT prolongation.

What effects can etomidate cause during recovery?

Myoclonic and tonic movements, as well as nausea and vomiting.

What are the potential effects of ketamine?

Hallucinations, dreams, and psychotic episodes.

What are the common adverse effects of propofol?

Local burning on injection, bradycardia, hypotension, and pulmonary edema.

What sensations are associated with fospropofol?

Perianal burning, stinging, tingling, and rash.

What is the primary method of inducing general anesthesia?

IV agents are administered first, followed by inhaled agents to maintain anesthesia.

What is nitrous oxide used for in anesthesia?

It is a potent analgesic that depresses the CNS to produce anesthesia and analgesia.

What is the onset time for nitrous oxide?

Rapid onset of action within 1-2 minutes.

What are the adverse effects of nitrous oxide?

Cardiovascular and respiratory depression, apnea, earache, sinus pain, vomiting, and malignant hyperthermia.

What is malignant hyperthermia?

A life-threatening emergency characterized by a sudden elevation in body temperature (>104° F) during or after general anesthesia.

What is the role of medical oxygen in healthcare?

Required for resuscitation and inhalation therapy.

What is medical air used for?

As a substitute for nitrous oxide during anesthesia and in ICU/NICU areas.

What is the purpose of medical CO2?

Used as an insufflation gas for minimally invasive surgeries.

What are volatile anesthetics?

Liquid at room temperature, converted into vapor for inhalation to produce anesthetic effects.

Name a volatile anesthetic.

Examples include halothane, desflurane, enflurane, isoflurane, sevoflurane, and methoxyflurane.

What are the uses of intravenous anesthetics?

To induce or maintain general anesthesia, induce amnesia, and as adjuncts to inhalation-type anesthetics.

What are some adjunctive agents in anesthesia?

Sedative-hypnotics, opioids, neuromuscular blocking agents, and anticholinergics.

What should be readily available during anesthesia administration?

Emergency equipment to maintain airway and provide mechanical ventilation.

What should be monitored during anesthesia administration?

PR, RR, BP, ECG, and cardiac output.

What comfort measures should be provided to patients during anesthesia?

Pain relief, reassurance, skin care, and supportive care for conditions like hypotension and bronchospasm.

What is important for preoperative patient teaching?

Patients may be unconscious or receiving teaching about a procedure.

What are local anesthetics also called?

Regional anesthetics

What is the primary function of local anesthetics?

To render a specific portion of the body insensitive to pain

Do local anesthetics cause loss of consciousness?

No, they do not cause loss of consciousness.

In what order do sensations get lost with increasing concentrations of local anesthetics?

Temperature, touch, proprioception, and skeletal muscle tone.

What is the recovery order after losing sensations due to local anesthetics?

Recovery occurs in the reverse order of loss.

What are the two main types of local anesthetics?

Topical and parenteral.

How are topical anesthetics applied?

Directly to skin or mucous membranes.

What is infiltration anesthesia?

Injecting the anesthetic directly into the tissues to be treated.

What is field block anesthesia?

Injecting the anesthetic around the area affected by the procedure.

What is nerve block anesthesia?

Injecting the anesthetic at a point along the nerve that runs to/from the region needing pain relief.

What is a peripheral nerve block?

Blockage of sensory and motor aspects of a particular nerve for pain relief.

What is central nerve block?

Injection of anesthetic into the roots of the nerves in the spinal cord.

What is epidural anesthesia?

Injection of the drug into the epidural space where the nerves emerge from the spinal cord.

What is caudal block?

Injection of anesthetic into the sacral canal, below the epidural area.

What is spinal anesthesia?

Injection of anesthetic into the spinal subarachnoid space or cerebral spinal fluid.

How are local anesthetics classified?

As esters or amides.

Name an example of an ester local anesthetic.

Procaine (Novocain)

Name an example of an amide local anesthetic.

Lidocaine (Xylocaine)

What is the first function lost when using local anesthetics?

Autonomic activity.

What is the last function lost when using local anesthetics?

Motor activity.

What can cause adverse effects from local anesthetics?

Inadvertent intravascular injection, excessive dose, slow metabolic breakdown, or injection into highly vascular tissue.

What should be readily available during local anesthesia procedures?

Emergency equipment to maintain airway and provide mechanical ventilation.

What precautions should be taken after spinal or epidural anesthesia?

Patients should be well hydrated and remain lying down for up to 12 hours.

What is important for skin care at the site of local anesthetic administration?

To reduce the risk of breakdown.