Anaesthesia What surgion should know!

1. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 1
Anaesthesia
(what surgeon should know! )
Types of anaesthesia
 Combined

2. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 2
General Anaesthesia :
🔵Elements (components) of general anaesthesia
Fig 1
Fig 1
🔵Prerequisite :
 Oxygen
 Suction
 Tilting trolly
 Resuscitation drugs
 Monitoring
 Anaesthetist
 Skilled assistant
 Drugs and machine

3. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 3
�Steps (sequence) of General anaesthesia
 Induction
 Muscle Relaxants
 Intubation
 Ventilation
 Reversal

Patients undergo 3 stages :
a)awake
b)excitement (not in children)
c) anaesthesia
�Induction agents
 Inhalational
 Intravenous

4. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 4
Inhalational agent(volatile anesthetic)
-The MCC of intra op bradycardia (tx: Atropine)
-Most have : myocardial depression, ⬆️cerebral flow,
⬇️renal blood flow
-MC way in children as they progress through stage b
quickly (adult iv )

5. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 5
Such as :
• nitrous oxide(NO2) :
odorless, colorless, non-flammable ga, laughing gas
fast, least potent , minimal myocardial
depression, tremors at induction. should be avoid
in pt with small bowl obstruction OR
pneumothorax as it diffuse into closed space and
my cause perforation
• Halothane : slow onset/offset, highest degree of
myocardial depression and arrhythmia, least
pungent (good for children)
Halothane hepatitis(volatile anaesthetic hepatitis, except
Sevoflorane ) – fever, eosinophilia, jaundice, high LFTs,
due to trifluroacetyl metabolite
• Sevoflorane :mc, fast, less laryngospasm, less
pungent(pleasant smell) >>>good for mask
induction
• Isoflurane : good for neurosurgery >>> lower
brain O2 consumption, no increase in ICP
• Enflurane : can cause seizure
• Desflurane: most rapid onset /offset, pungent
odder, so not use in induction, for maintenance
anaesthesia

6. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 6
Intravenous agent
 Sodium thiopental (barbiturate) :
fast acting
S/E: ⬇️cerebral blood flow and metabolic rate
⬇️B/P
 Propofol (diprivan) :
very rapid distribution and on/off, amnesia,
sedative
S/E: hypotension(MC) , respiratory depression
metabolic acidosis
Propofol infusion syndrome: associated with high
dose infused more than 48 h, metabolic acidosis,
bradycardia, rhabdomyolysis, hyperlipidaemia,
hepatomegaly(not splenomegaly. children higher
risk. exogenous catecholamine (or steroids)
trigger it.
screening : daily lactate and creatine phosphate
(cpk) my prevent this complication.
Not an analgesic
Not use in patients with egg allergy, pregnancy,
parkinsonism
⬇️Nausea, bronchodilator (advantage in day
case anaesthesia)
Pain on iv Injection
 Ketamine:
dissociation of thalamic /limbic system
Nightmares
Place pt in a cataleptic state(amnesia, analgesia)
No respiratory depression

7. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 7
S/E: hallucinations, catecholamine release
(⬆️CO2,tachycardia), ⬆️airway
secretions⬆️cerebral blood flow
C/I in pt with head injury
Good for children
Little myocardial depression making it suitable for
those who are hemodynamically unstable.
Analgesic effect, good for procedure outside the
hospital
 Dexmedetomidine (precedex)
Analgesia and anaesthesia without blunting
hypoxic derive good for early extubation protocol
 Etomidate, unconscious, Anesthesia, amnesia
but not analgesic, Fewer hemodynamic changes,
fast acting
Can lead to adrenocortical depression
�rapid sequence intubation :
For recent oral intake, GERD, Delayed gastric
emptying, pregnancy, bowel obstruction
Typical sequence : cervical in line mobilization>
pre-oxygenate> cricoid pressure > induction
(Etomidate) >paralysis (succinylcholine) >CO2
detector
Example : closed head injury with abtunded pt:
Etomidate(cardiovascular stability so good in
trauma, ⬇️cerebral blood flow) +
Succinylcholine(⬆️ICP but it’s counteracted by
Etomidate) >oral tracheal intubation

8. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 8
Avoid nasal intubation, may induce cribriform
palate fracture
Laryngeal mask : only temporalizing

9. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 9
�Muscle Relaxants (paralytics)
MCC of hypersensitivity reaction post op
(II: latex, III:A/B)
Diaphragm : last muscle to paralysed and first to
recover
Face and neck : first to paralysed and last to recover
No analgesic effects (pt aware of surrounding)
2 types:
1. Depolarizing
2. Non-depolarizing
Depolarizing :
only one “Succinylcholine” (Suxmethonium)
Fast, short acting, fasciculation, ⬆️ICP,
No reversal agent
Paralysis by repetitive stimulation of action potential,
influx of K, and transient ⬆️in K
Safe in acute sitting of spinal, burn and head injury, as
number of motor end plate ⬆️3-5days after event
Metabolized by plasma pseudocholinesterase
S/E:
 Malignant hyperthermia(AD)

10. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 10
Caused by all volatile Anaesthetic (Halothane,
Enflurane, Isoflurane, desflurane) and
succinylcholine
Defect in Ca metabolism
Ca released from sarcoplasmic reticulum >>>
muscle…“excitation – contraction” syndrome
First sign : ⬆️End tidal CO2, then
Fever, tachycardia, rigidity, acidosis,
hyperkalemia, rhabdomyolysis
Trismus maybe the first sign, so cancel surgery
and admit for 24h
Genetic test available but muscle bx more
common (coffine-halothen test)
CPK not sensitive
TX: dantrolene (2.5mg/min repeat every 5
min, max 10 mg/kg,) cooling blankets,
HCO3, Glucose, supportive care.
 Hyperkalemia
So not used in patients with severe burn,
neurological injury, neuromuscular disorders,
spinal cord injury(safe within first 24h), massive
truama, acute renal failure,crush injury)
 Open angel glaucoma can become closed angle
Not C/I in chronic RF, children
🔆Atypical pseudocholinesterase (asian) can
prolong paralysis
No reversal, 30% mortality, may present 24h after
Anesthesia

11. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 11
Non-depolarizing
Inhabit neuromuscular junction by competing
with acetylcholine
Prlong myasthenia gravis
 Cis-atracurium (numbex)
Undergoes Hoffman degeneration
Can be used in liver and renal failure
Histamine release
 Rocuronium : fast, hepatic metabolism (good for
RCI in pt with C/I to succinylcholine)
 Pancuronium : slow, renal metabolism
Sympathetic nerves stimulation (10%) high B/P
SE: Tachycardia(mc), so don’t use in trauma as
tachycardia can be confusing cause of
hemodynamic instability
Reverse druge for Non-depolarizing agents
 Neostigmine : block acetylcholinesterase
>>>⬆️acetylcholine causes bradycardia
Atropine concomitantly to counteract this effect
 Endrophonium : same
 Atropine with Neostigmine or Endrophonium to
counteract acetylcholine overdose

12. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 12
Local Anaesthetic
⬆️Action potential threshold, preventing Na
influx
Length of action : bupivacaine>lidocaine
>procaine
CNS (cross BBB) earlier than cardiac
symptoms (arrhythmia, asystole)
First sign of lidocaine toxicity is perioral
paraesthesia (numbness, tingling)
Effect depend on location (vascularity of the
location) : intercostal space >>>subcutaneous
tissue
Infected tissues are hard to anesthetize
secondary to acidosis
⬆️Toxicity in pregnancy, so ⬇️therapeutic
dose
S/E: tremors, seizure, tinnitus, arrhythmia (CNS
symptoms occur before cardiac)
Epinephrine allows higher dose to be used,
stays locally
1:100000 adrenaline
No epinephrine with arrhythmia, unstable
angina, uncontrolled hypertension, poor
collaterals (penis, ear), uteroplacental
insufficiency

13. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 13
Amides( have “i” in first part of name) :
lidocaine, bupivacaine, mepivacaine
Metabolized in liver
Rare allergic reactions
Esters: tetracaine, procaine, cocaine
Metabolized by plasma cholinesterase
More allergic reactions due to PABA analogue
Dose:
For 1%Lidocaine :
with Epinephrine 0.7cc/kg
Without 0.5 cc/kg
Half of these dose if 2%lidocaine

14. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 14
Benzocaine / prilocaine toxicity : falsely high O2sat
(methaemoglobinaemia). Cyanosis despite 100%O2
sat. TX : iv methylene blue
Example of dosing : max dose of 1% lidocaine with
Epinephrine for 70kg male pt = 70×0.7= 49cc

15. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 15
Narcotics (opioids)
Act om mu-opioid receptors
Analgesia, respiratory depression ((⬇️CO2 derive),
No cardiac effects, blunt sympathetic response
Metabolized by liver and excreted by kidney
Overdose of narcotics : TX Narcan (naloxone) (all)
Avoid in MAOIs, can cause hyperpyrexic coma
 Morphine : analgesia, euphoria, respiratory
depression, miosis, constipation, Histamine
release (hypotension), ⬇️cough
 Demerol: analgesia, euphoria, respiratory
depression, miosis, tremors, fasciculation,
convulsion
No Histamine release
Can cause seizure (build up of
normeperidine)>avoid in pt with renal failure
 Methadone : stimulate morphine, less euphoria

16. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 16
 Fentanyl: fast acting, 80× strength of morphine,
no cross reaction with morphine, no histamine
release
 Sufentanil : most potent

17. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 17
Benzodiazepines
Anticonvulsant, amnestic, anxiolytic, respiratory
depression, not analgesic, liver metabolism
 Versed(midazolam) : short acting, C/I in
pregnancy, crosses placenta
 Valium(diazepam) :intermediate acting
 Ativan(lorazepam) :long acting
Overdose?
Flumazenil, competitive inhibitor (competition at
GABA binding sites)
may cause seizure and arrhythmia
C/I in pt with ⬆️ICP, status epilepticus
Regional anaesthesia
Types:
 Epidural
 Spinal (subarachnoid)
 Peripheral nerve block
 Intravenous (Biers) block
 Plexus block
Epidural and spinal Anesthesia

18. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 18
Epidural :
Outside the dura, in epidural space
Sympathetic denervation(unopposed vagal
stimulation) , vasodilation
Block motor, sensory, sympathetic, but not
parasympathetic
Cane use morphine (respiratory depression) and
Lidocaine (⬇️hear rate and B/P) in epidural
Dilute concentration allow sparing of motor function
T5: affect cardiac accelerator nerves(T1-T4: heart
accelerator), causes bradycardia
Lower pulmonary and cardiac complication
Hypotension, bradycardia Tx: stop epidural, fluids,
phenylephrine, Atropine
C/I Hypertrophic cardiomyopathy, cyanotic heart
disease(( sympathetic denervation ⬇️afterload which
worsens these conditions)
Risk of bleeding (INR >1.5) , systematic or local
infection, hypovolemia,, ⬆️ICP
Good for post op pain control ( can be repeated
unlike spinal)
Sensory >motor (motor still intact), not for LL
paralysis
Complication :
Haematoma (MRI) :bilateral LL paralysis, TX
decompressing Laminectomy
Retention: TX :folly’s

19. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 19
Unilateral LL paralysis : inadvertent placing
needle
Spinal anaesthesia :
Injection into subarachnoid space (below L2, avoid
hitting the spinal cord)
Spread by baricity* and pt position
Motor and sensory loss (Neurological block is
above motor block)
Any surgery below umbilicus (C.S, appendectomy,
hysterectomy)
One shot only, can’t infuse it like epidural
C/I same as in epidural
Complication for epidural and spinal
Hypotension, headache, urinary retention, abscess,
haematoma, respiratory depression (high spinal)
Post Spinal headache :
RF: Female, <50,use of large needle
Caused by CSF leak, worse sitting up
TX: rest, fluid, caffeine, blood patch
Caudal block (subtype of epidural)
Through sacrum
Good for paediatric hernia and perianal surgery

20. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 20
Intravenous regional anaesthesia (biers block)
for short procedure such as that in hand or feet,
prilocaine the drug of choice as its less cardiotoxic
TAP block
Rectus sheeth block
ASA SCORE
(American Society of Anaesthesiologists)
Allow assessment of outcome, don’t predict risk
Study found correlation with op duration, blood loss,
hospital stay, ICU stay, woundinfection, pulmonary
/cardiac complication, mortality
No correlation with anastomotic leak
Example on ASA :
 Appendectomy on healthy pt: IE

21. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 21
 Controlled DO, HTN, obesity, pregnancy, mild
asthma : II
 MF, Smoker underwent emergent hernia repair:
: IIE
 Stable Angina, previous MI, moderate COPD,
morbid obesity, poorly controlled DM,/HTN :
III(limit activity)
 Unstable angina, sever COPD, Liver/Renal
failure(ESRD), CVA, MI :IV
 Rupture AAA, saddle PE, trauma : V (not
expected to live >24h without surgery
 Pt on dialysis for renal failure Undergoes
elective abdominal aortic aneurysm repair : IV
Mallampati classification of airway exam
I. See tonsillar pillar
II. Can’t see tonsillar pillar
III. Base of uvula
IV. Can’t see base of uvula

22. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 22
�ETCO2
Best to determine esophageal vs. Tracheal intubation
Intubated pt with sudden drop in ETCO2 : disconnected
from the vent
Could be also due to PE (hypotension)
Patient control anastasia (PCA)
C/I: <5 years, critically ill, confused, learning
difficulties, ⬇️Manual dexterity

23. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 23
Miscellaneous
�In aortic stenosis use anaesthetic that avoid
Hypotension
�Interscalene nerve block C 5-T1(diaphragm c3-c5,
close) diaphragm dysfunction well-tolerated but worry
if pre-existing lung disease
�Visceral pain : internal organ, >>>opiod
�Somatic pain: musculoskeletal >>> NSAID, opioid
🔵Appendicitis : start as visceral pain (peri umbilical)
then somatic (RLQ)
🔵Pain scale 1-10, keep between 1-3
�Endotracheal tube should be placed 2 cm upove the
carina
�Most PACU complication : nausea and vomiting

24. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 24
🔵 WHO Analgesic Ladder
Sources : absite, rush, de virgilio, SCHWARTZ'S,
surgical recall, EMRCS, SURGERY ESSENCE, and
others...

25. Anaesthesia
*Baricity refers to the density of a substance compared to the density of human cerebrospinal fluid. 25
Jihad M. H. Al-Jarrah
MD, Jo-board, MRCS
G. Surgery specialist, colorectal fellow
Royal medical services
0797892775