L3 GA, LA Flashcards
General anesthesia definition
loss of response to and perception of external stimuli.
General anesthetic drugs should ideally produce ?
• Unconsciousness
• Analgesia
• Amnesia
• & muscles relaxation.
• Suppression of undesirable reflexes
Drug Groups used for Optimal anesthesia?
Pre-anesthetic medications
Skeletal muscle relaxants
IV anesthetic agents
Potent general anesthetics
IV anesthetic agents: Used for?
induction
Potent general anesthetics via inhalation Used for ?
maintenance of anesthesia
Ideal anesthetic should ?
• Induce anesthesia smoothly, rapidly & for enough time
• Allow quick recovery & be safe (no adverse effects)
• It should be non-inflamable
• For sedation in GA we use?
barbiturates ( thiopental)
• For vomiting in GA we use ?
anti- emetic Domperidone
• For analgesia in GA we use ?
opiads (fentanyl)
• To prevent bradycardia in GA we use ?
atropine
• For muscles relaxation in GA we use ?
muscle relaxant (succinylcholine)
• produce tachycardia?
Adrenaline
surgery is done in which stage of GA ?
III- Stage of surgical anesthesia:
Stages of anesthesia
1-Induction of anesthesia (anesthetics, muscles relaxants & analgesics)
2-Maintenance
3-Recovery
Pre- anesthetic medication ?
drugs given before anesthesia to produce balance anesthesia
& to reduce the side effects of G.anesthetics.
They calm the patient, relieve pain,& protect against undesirable effects of the subsequently administered anesthetics or surgical procedure.
Used to induce anesthesia rapidly & pass endotracheal tube?
thiopental (For sedation)
Mechanism of action Of general anaesthetic ?
-facilitate GABA-A receptor, increase Cl- channels & inhibit synaptic transmission.
-open K-channels
-antagonizes excitatory effect of glutamic acid on NMDA receptors?
Ketamine
measures relative potency of anesthetic agents ?
MAC
Nitrous oxide is less potent( largeMAC)
Halothane is more potent ( LessMAC)
( Lower the MAC, more potent the anesthetic agent)
-A drug which is less soluble in blood, will have…………………… e.g. Nitrous oxide.
-A drug which is more soluble in blood, will have ……………………. e.g. Halothane.
-rapid induction & rapid recovery
-slow induction &slow recovery
It is a potent analgesic but a weak anesthetic?
Nitrous oxide
safest anesthetic provided if administered with at least 20 % oxygen?
Nitrous oxide
لانه ممكن يسبب hypoxia
لازم O2 معه
-It is a potent anesthetic & weak analgesic
-It is used more in obstetrics because (relaxes uterine & skeletal muscles)
-It is suitable in children having pleasant odor.
-It is hepatotoxic but not hepatotoxic in children??
Halothane
(but due to side effects not much used nowadays)
side effects of Halothane?
Cardiac arrhythmia
& malignant hyperthermia.
-given for treatment of malignant hyperthermia?
Dantroline
nephrotoxic drug and It is more muscles relaxant due to curare like action?
Enflurane
side effects of Enflurane?
CNS excitation, so should not be used in seizure like disorders.
((good for ischemic heart disease patient))
Because
-It dilate coronary vasculature
-increase coronary blood flow
-increase myocardial O2 consumption
Isoflurane
Drug Cause hypotension Does not increase intracranial pressure?
Isoflurane
اغلبهم الانهيليشنز يقللون BP وهذا من ضمنهم
………….. can cause transient sympathetic stimulation, thus may ↑ heart rate & BP ( inhaled GA )
Desflurane
الوحيد اللي يزود ضغط الدم،بس بالنسبه لICP كلهم ممكن يزودونه
اكسبت isuflurane
Inhaled anesthetics except………………depress respiration & ↑ PaCO2
N 2 O
• Inhaled anesthetics ↑ cerebral blood flow & ↑ ICP
•………….. causes lesser ↑ in ICP but ……………. does not cause it.
N2O
Isoflurane
Malignant hyperthermia Consists of:
tachycardia ,
hypertension,
hyperthermia,
muscle rigidity,
hyperkalemia & acidosis
الصراحه مدري شلون acidosis مع hyperkalemia بس الشكوى لله
(Dantrolene is specific antidote) يعالج الموضوع الذيب
metabolized to fluoride ?
Enflurane \ Methoxyflu- rane
nephrotoxic وكلهم
Recovery from intravenous anesthetics is due to ………. from CNS to muscle & fat.
redistribution
rapid injection Intravenous Anesthetics may cause ?
respiratory & cardiovascular depression.
Intravenous Anesthetics
• Barbiturates: Thiopental
• Benzodiazepines: Medazolam, Diazepam, Lorazepam
• Opioids: Fentanyl, Sufentanil , Remifentanil
• Others: Propofol, Ketamine.
-Short acting barbiturates It is a potent anesthetic but a weak analgesic Commonly used IV for induction of anesthesia ?
Thiopental
تم استبداله
Adverse effects of Thiopental
• Can cause cardiovascular & respiratory depression
• ↑ acute intermittent porphyria & (((bronchospasm)))
ممنوع للي عندهم asthma
Used as pre-anesthetic medication for sedative & amnesic effects & given before induction of anesthesia ?
Diazepam
Medazolam افضل
(specific antagonist) is used to enhance recrvery from over sedation with benzodiazepines?
Flumazenil
Adverse effects of Opioids ( Fentanyl ) ?
• Chest wall rigidity & respiratory impairment
(specific antagonist) of opioids ( fentanyl)
can be used to ↑ recovery?
Naloxone
Ketamine properties :
-Short acting nonbarbiturate G. anaesthetic.
-antagonizes excitatory effect of glutamic acid on
-Produce dissociative anesthesia ( patient seems awake)
-Useful anesthetic for cardiogenic , septic shock patients , patients with asthma & good for children also young adults.
Ketamine Adverse effects:
not be used in hypertensive & stroke patients
لانه يزود الضغط
It decreases B.P without depressing myocardium
It decreases intracranial pressure. It is widely used & has replaced thiopental as a 1 st choice for induction of anesthesia & sedation?
Propofol
Adverse effects of Propofol ?
Muscles twitching, hiccups.
Local anesthetics definition ?
These are agents generally applied locally.
They block nerve conduction of sensory impulses from periphery in a limited area to CNS without producing unconsciousness. affect touch, pressure and thermal sensations
-was the first agent used for Local anesthetics in (1884)
Cocaine
Esters LA?
Cocaine ( 2 - medium )
Procaine ( 1 - short )
Tetracaine ( 16 - long )
RBT. Long
(Short - long acting مهمين بس)
Amides LA?
Lidocaine ( 4- medium )
Mepivacaine( 2- medium )
Bupivacaine (16 - long )
Prilocaine ( medium )
Ropivacaine ( 16 - long )
Pharmacokinetics of LA?
In infected tissues, PH will be low and penetration will be less
LA combination with local V.C ( Epinephrine, nor E) effects?
} To prolong the action of LA
} To increase the depth of LA
} To reduce the systemic toxicity of LA
} To obtain hemostatic effect
Don’t produce unconsciousness
Rotes of administration of LA
- Topical application (Nasal mucosa, wound margin, eye surgery )
- Infiltration (LA will be Injected in the vicinity of peripheral nerve Endings)
-
Regionalanaesthesia
( large part of the body will be anaesthetised; it is divided into:
-central technique “ neuroaxial blocks ” And
-peripheral technique “plexus block or nerve block”.
Neuroaxial blocks include ( epidural/spinal anaesthesia )
For Prophylaxis in LA We give ?
IV benzodiazapines
Adverse effects of LA in CVS?
(cause vasodilatation and ↓BP ) الاهم
-All LA block Na+ channels, so depress abnormal cardiac pacemaker activity
-Also, depress the strength of cardiac contraction
-Long-acting agents may produce ventricular arrhythmias
-Long-acting agents of LA may produce ventricular arrhythmias except?
Cocaine; blocks NE reuptake and accordingly,
cause vasoconstriction and ↑BP
Cocaine dilate pupil
Spinal Anaesthesia Advantages / Disadvantages
Advantages:
1- Less cost
2- Rapid recovery with no post- operative nausea and vomiting
3- No depression of respiration and airway are patent
4- Less post-operatively deep venous thrombosis “DVT” and pulmonary embolism
Disadvantages:
1- Difficult technique
2- Doesn’t suit any patient/surgeon
3- Uncomfortable if long procedure (>2hr)
4- Infection
LA preferred For obstetric procedures ?
Bupivacaine and Ropivacaine
Complications of neuraxial anaesthesia?
- Post dural puncture headache; occipital,
((worse on standing and relieved by lying down, more in young females)) - Spinal hematoma/Epidural abscess
- Facial paralysis
- Needle –stick injury & needle fracture
Uses of LA in dentistry
-((Reduce bleeding: Due to addition of vasoconstrictor)) اهم
-Differentiate between pain from upper or lower tooth
(pulpitis makes difficult to differentiate)
Reduction of arrhythmias during general anesthesia
Reduce depth of general anesthesia (less dose needed)
Compilation of local A?
-Failure to achieve LA; related tp hot pulp or apical abscess
(pus decreases action of LA)
-Hematoma
-Trismus
Mechanism of action of cocaine?
It inhibits reuptake of norepinephrine Also cause anesthesia.
