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81 Cards in this Set
- Front
- Back
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what is nitrous oxide
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gaseous anesthetic used as supplement to other anesthetic agents
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what types of proceedures is nitrous oxide used for?
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during early purturition or dental procedures
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what effects dose nitrous oxide have?
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effect analgesic and amnestic but no muscle relaxation
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what type of onset and off set does nitrous oxide have?
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rapid onset and offset
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what is an adverse effect of nitrous oxdie that is caused by expansion of air pockets in closed spaces?
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increased intracranial pressure
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why is nitrous oxide not effective as a single anesthetic agent to produce stage 3 anesthesia?
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it would produce hyopxia while getting to stage 3
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what happens with cessation of nitrous oxide?
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diffusion hypoxia - rapid offset displaces inspired oxygen from the alveoli
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how is diffusion hypoxia prevented?
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breathing 100% oxygen following cessation
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what are the cardiovascular and respiratory effects of nitrous oxide?
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minimal
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does nitrous oxide produce malignant hyperthermia?
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no
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what occurs with chronic exposure ot nitrous oxide?
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lung toxicity due to methionine synthase inhibition, blood dyscrasias, bone marrow suppression, increased incidence of spontaneous abortion, peripheral neuorpathies
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what occurs with recreational use of nitrous oxide?
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peripheral neuropathy
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what are the properties of IV anesthetics?
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good amnesia, poor analgesia, no muscle relaxation, rapid onset and offset
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what barbituates are used for IV anesthetics
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thiopental thiamylal and methohexital
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what is theopental
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barbituate IV anesthetic
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what is thiamylal?
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barbituate IV anesthetic
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what is methohexital
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barbituate IV anesthetic
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do barbituate anesthetics have low or high lipid solubility
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high - they are radioly redistrubuted from the blood to adipose
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do barbituate anesthetics produce balanced anesthesia?
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no they only produce loss of consciousness and amnesia
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what terminates barbiturates when they are used as anesthesias?
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redistribution, not metabolism
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what are the effects of barbiturates on the respiratory and cardiovascular systems?
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respiratory and cardiovascular depression may occur if given rapidly or in large doses
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which benzodiazeprines are used as IV anesthetics?
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diazepam, midazolam, lorazepam
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what are benzodiazepines used for in relation to anesthesia?
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used for induction or anesthesia or conscious sedation
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which benzodiazepine is preferred?
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midazolam
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do benzodiazepines produce analgesic action?
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no, only sedatio and amnesia
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what can be used to terminate the action of benzodiazepines?
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flumazenil
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what is propofol?
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an IV anestetic that is used to induce general anesthesia and produce conscious sedation
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what adverse reactions can occur with propofol?
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anaphylactoid reactions due to the emulsifying agent
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what effects on hemodynamics can occur with propofol?
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they can inhibit platelet funcitona nd increase bleeding time - short lived phenomenon
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what is ketamine?
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IV anesthetic that produces a dissociative state - patient doesn't responsd to noxious stimuli
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what is unique about ketamine?
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muscle tone is sustained and patient is awake with eyes open but doesn't respond to noxious sitmuli
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what is th m.o. of ketamine?
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antagnoist for glutaminic acid receptors (NMDA)
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what can occur from recovery from ketamine?
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hallucinations - reduced if diazepam is given before
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what are the cardiovascular effectso f ketamine?
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increased BP, HR and CO - due to increased of NE and E thus increased SNS tone to the heart and peripheral vasculature; increases cerebral blood flowand intracranial pressure
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what is the effect of ketamine on respiration?
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respiratory depression is not as common as with other drugs
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what drugs are given for neuroleptic analgesia and anesthesia?
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droperidol plus a short acting opiod analgesic (fentanyl or remifentanyl)
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what are neuropletic anagesics used for?
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procedures not requiring muscle relaxation
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how can conscious sedation be turned into anesthesia?
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by addition of NO or reduced amounts of another general anesthetic
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what can occur if drugs used for conscious sedation are administered rapidly?
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larnygospasm
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what are the cardiovascular effects of neuroleptic analgesics?
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myocardial contractility and NP are well maintained with some bradycardia due to increasd PNS stimulation
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incrased PNS stimulation
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neuroleptic drugs
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increased SNS stimulation
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ketamine
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what are the respiratory effects of neruoleptic analgesia?
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respiratory depression is prolonged
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what is halothane?
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potent volatile anestetic with high lipid solubility
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what is halothane used for?
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as a general anesthetic
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what are the cardiovascular effects of halothane?
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reduced myocardial contractility, reduced CO and BP, bradycardia
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what is the action of halthane to the response of catecholamines?
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it sensitizes the heart to catecholamines - induced ventricular arryhthmias
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what is the major side effect of halothane?
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hepatoxicity
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what can occur with use of flurane anesthetics?
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vasopressin resistant polyuria (diabetes insipidus like)
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what is the major side effect of enflurane?
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causes mild seizure activity
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what is the effect of enflurane on cardiac activity?
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enflurane reduces myocardial contractility, CO and BP and causes bradycardia
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what is the cardiac effect of isoflurane, desflurane and sevoflurane?
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reduces peripheral vascular resistance without changing HR
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what is dantrolene?
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muscular skeletal relaxant that is used to treat malignant hyperthermia
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what is the action of most volatile anesthetics to respiration?
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reduces rate and depth of respiration and decreases medullary responsiveness to both arterial CO2 and hypoxic drive mechanism
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what are the renal effects of volatile anesthetics?
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reduced GFR and ruine formation
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what are the brain effects of volatile anesthetics?
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increase cerebral blood flow and volume and intracranial pressure
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what are the effects of volatile anesthetics on the liver?
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reduce blood flow and transiently impairs liver funciton
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what are the skeltal muscle effects of volatile anesthetics?
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reduces skeletal muscle tone by actions in the CNS and at the post NMJ by blocking membrane potential
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what is malignant hyperthermia?
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genetically susceptible defectin the SR that limits reuptake of calcium, the extra ATP generated to take up the calcium increases body temperature
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what can precipitate malignant hyperthermia?
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administration of succinylcholine
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what is the action of volatile anesthetics on uterine smooth muscle?
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relaxes smooth muscle, slows progression of labor
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define general anesthesia
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reversible losso f consciouness with analgesia, amnesia, inhibition of sensory and autonomic reflexes and decreased skeletal muscle tone
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define conscious sedation
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altered or diminshed state of consciousness with analgesia, amnesia, and retained responsiveness to verbal commands
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when is conscious sedation used?
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when skeletal muscle tone doesn't need to be reduce (reduces danger of hypoxia0 - cardiovascular procedures, GI procedures, pulmonary procedures and many dental procedures
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what is the first stage of general anesthesia?
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analgesia without loss of consciousness - conscious sedation is a deep phase of this stage
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what is the 2nd stage of general anesthesia?
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excitation - unconscious, pupillary dilation, BP and respiration irregular - essential to get through fast!!
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what is stage 3 of general anesthesia?
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surgical anesthesia - slow regular respiration and stable BP; suppression of autnomic and sensory reflexes
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what is stage 4 of general anesthesia?
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medullary depression - dose dependent suprresion of BP and respiration, respiration needs to be maintained
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what is the potency of general anesthetics related to
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potency is proportional to lipid solubility in the gaseous phase
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what is MAC 50
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minimum alveolar concentraion producing immobility to a standard noxious stimuli in 50% of patients
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what determines the depth of anesthesia?
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depth is determined by concentration of anesthetic in the brain
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what determines th onset of general anesthetics?
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onset is proportional to the partial pressure of the volatile anesthetic within inspired air; dependent on water solubility - less soluable more rapid onset
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water solubility determines what
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rate of onset
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lipid solubiltity determines what
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potency
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what happens to onset when pulmonary ventilation is increased?
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pulmonary ventilation is increased = onset is increased
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what happens to onset when pulmonary blood flow and brain blood flow are increased
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onset is increased
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what happens at equilibrium of a volatile anesthetic agent?
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at equilibrium the blood concentration of the agent is determined by the alveolar concentration = proportional to pulmoanry ventilation
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what determines the blood concentration of a volatile anesthetic at equilibrium
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it is porportional to pulmonary ventilation
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what is the primary mechanism of eliminatio of volatile anestetics?
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pulmonary ventilation (hepatic route is minor)
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how are onset and offset related?
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same properties that determine onset determine offset - rapid onset = rapid offset
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what are the lipid solubiltiy and water solubitlity of nitrous oxide?
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poor lipid solubility and poor water solubility
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