Analgesia, Anesthetic Agents, and Special Techniques

CNS Hypersensitivity

A state caused by constant nociceptive input from the periphery in which neurons in the spinal cord become hyperexcitable leading to heightened sensitivity to low-intensity stimuli that wouldn’t normally elicit a pain response

Distress

An extreme form of stress that leads to anxiety and suffering and can result from untreated or chronic pain

Emergence Delirium

Disorientation that occurs during anesthetic recovery as consciousness returns; characterized by vocalization, aggression, thrashing, and locomotor activity

Mediators

Chemical substances released from damaged cells or inflammatory cells that cause a response such as increasing the sensitivity of peripheral pain receptors

Modulation

The third step in nociception in which sensory nerve impulses are amplified or suppressed by other neurons

Multimodal Therapy

Treatment of pain with analgesics that target two or more types of pain receptors; allows for lower doses and overall decreases the risk of adverse effects

Pathologic Pain

Pain that is amplified and persistent; occurs due to malfunction of or damage to the nervous system; maladaptive because it serves no useful function while causing suffering

Physiologic Pain

The protective sensation of pain that normally occurs when there is a possibility of or actual tissue injury; adaptive because it promotes survival by preventing injury and promoting healing of the injured body part

Primary Hyperalgesia (Peripheral Hypersensitivity)

Increased sensitivity to a painful stimulus that occurs when the threshold of the peripheral pain receptors is lowered as a result of injury to peripheral tissues thus increasing sensitivity

Secondary Hyperalgesia

CNS Hypersensitivity or “windup”

Somatic Pain

Pain originating from the musculoskeletal or integumentary system; subclassified as superficial and deep

Transduction

The first step in nociception in which noxious thermal, chemical, or mechanical stimuli are transformed into electrical signals called action potentials

Transmission

The second step in nociception in which sensory impulses are conducted to the spinal cord

Visceral Pain

Pain originating from the internal organs

Adjunct

A drug that is not a true anesthetic but is used during anesthesia to produce other desired effects such as sedation, muscle relaxation, analgesia, reversal, neuromuscular blockade, or parasympathetic blockade

Analeptic Agent

A drug that causes general CNS stimulation

Anesthetic Agent

Any drug used to induce a loss of sensation with or without unconsciousness

Anticholinergic Agents

An adjunct that lessens parasympathetic effects by blocking muscarinic receptors of the parasympathetic nervous system

Apneustic Respiration

A breathing pattern most often seen during dissociative anesthesia in which there is a pause for several seconds at the end of the inspiratory phase followed by a short, quick expiratory phase

Cataleptoid State

A state produced by dissociative agents in which the patient does not respond to external stimuli and has variable degrees of muscle rigidity

Dysphoria

Anxiety, uneasiness, and restlessness most often produced by opioids

Fasciculation

Involuntary muscle twitching

Preanesthetic Medication

An anesthetic agent or adjunct administered during the preanesthetic period to provide one or more of a variety of desired effects including analgesia, sedation, and muscle relaxation

Assisted Ventilation

A type of ventilation in which the anesthetist ensures that an adequate volume of air is delivered to the patient although the patient initiates each inspiration

Atelectasis

Collapse of a portion or all of one or both lungs

Controlled Ventilation

A type of ventilation in which the anesthetist controls the RR, tidal volume, and peak inspiratory pressure; the patient makes no spontaneous respiratory efforts

Infiltration

Injection of a local anesthetic into tissues often in proximity to a nerve

Intermittent Mandatory Ventilation

Positive pressure ventilation throughout the entire anesthetic period as the sole source of the patient’s ventilatory needs

Manual Ventilation

Forced delivery of oxygen and anesthetic gases by squeezing of the reservoir bag; may be used to provide periodic or intermittent mandatory ventilation

Mechanical Ventilation

Forced delivery of oxygen and anesthetic gases by use of a mechanical ventilator; usually used for intermittent mandatory ventilation

Sympathetic Blockade

Loss of function of sympathetic nerves supplying the heart and blood vessels resulting from diffusion of local anesthetic into the thoracic spinal cord; signs include bradycardia, decreased cardiac output, and hypotension; blockade of the caudal sympathetic nerves results in less severe hypotension and tachycardia