Anaesthetics COPY Flashcards
Name some anti emetics ?
Which is best for post op nausea / vomiting?
vertigo?
travel sickness ?
ondansetron cyclizine domperidone metoclopramide prochlorperazine
ondansetron
prochlorperazine
cyclizine
what things do you need to do pre op?
Optimise medical conditions Adjust medication Check investigations Check weight EXPLAIN AND CONSENT
parts of relevant anaesthetic Hx ?
previous anaesthetics, FHx
Airway problems
PONV
Malignant hyperpyrexia - this is a dangerous complication of anaesthesia due to an underlying muscular disorder.
(Inherited skeletal muscle disorder. May reverse with Dantralene. Triggered by volatiles and suxamethonium.Hyperkalaemia, hypoxia, temperature, rhabdomyolysis)
Suxamethonium apnea (Patient does not have enzyme to break down therefore use propofol (Inherited disorder of acetylcholinesterase)
Allergies
Anaesthetic agents, analgesics, antibiotics, latex and eggs (propofol)
What to do for pt on warfarin for AF for operation
Stop and use LMWH
What features could make a difficult airway?
Anatomical
small mouth, small chin, large tounge, big neck
Lack of movement in neck / mouth
poor dentition
What 3 tests can be used to assess airway for intubation
mallampati (oropharynx) - open mouth and see differing amounts of the airway
extention of upper cervical spine
(<90 degrees)
thyromental test (Distance from tip of thyroid to tip of mandible at gull extension Normal > 6.5cm, under 6cm = difficult laryngoscopy)
3 parts of anaesthetic triad
anaesthesia
analgesia
muscle relaxation
With GA what 2 options of route are there?
IV - propofol
Inhaled (iso/sevo/desfluorane) @young children/ needle phobics
During induction of GA what should you do?
pre oxygenate / oxygenate
secure / manage airway
What drug is usually given with propofol for maintenance of GA
Remifentanil
What level of GCS do you need to provide airway control
Under 8
Physical manoeuvres for airway control
head tilt
chin lift
jaw thrust
When would be cautious using a nasopharyngeal tube?
base of skull fracture
3 ways to determine correct placement of ET tube?
Chest movement
Misting of mask
Trace on capnography
2 places an ET tube can go thats wrong
oesophagus 1 bronchus (too far in)
which local anaesthetic only lasts for a short period of time?
lidocaine
which local anaesthetic can provide 2 hours anaestheia and 12 hours of analgesia
bupivocaine
use for regional blocks
advantages of regional anaestheisa over GA
Avoids GA Can be awake Avoid airway problems Less nausea and vomiting Better peri-operative pain control
Where does an epidural go? spinal ?
between ligaments and dura
through dura
3 reasons muscle relaxants are used for surgery ?
Relax opening to trachea (glottis)
Relax muscles for surgery
Patients do not fight ventilators
Egs of muscle relaxants
suxamethonium - used for emergencies
Atracurium, rocuronium, vecuronium
Reversal of muscle relaxants
neostigmine
How do NSAIDS work ?
Inhibit cyclo-oxygenase
Side effects of opiodss
CNS - sedation, miosis CVS- bradycardia, hypotension Resp - brady / apnoea GI - N+V, constipation Urinary - retention Skin - itching
Egs of weak opiods
codeine
tramadol
rule of 1/3s for fluids
2/3 intracellular (28L)
(Na/Cl poor, K rich)
1/3 extracellular (14L)
(Na/cl rich, K poor)
- 2/3 interstitial
- 1/3 intravascular
Egs of crystaloid fluids
NaCl
dextrose
hartmanns
What is a crystaloid fliod? colloid?
Ions or small molecules dissolved in water
Larger insoluble molecules retained within plasma for longer
Egs of synthetic colloid fluids
blood, albumin
Synthetic
(starch
gelatin - these are never used)
risk of anaphylaxis!
Difference between t1/2 resp failure and mx with NIV
1
Hypoxia without hypercapnia
CPAP continuous
2
Hypoxia with hypercapnia
NPPV (BiPAP biphasic)
CPAP vs NPPV
CPAP
Increases intrathoracic pressure by maintaining a positive end expiratory pressure allowing the alveoli to stay open rather than collapse.
improves FRC and oxygenation
reverse resp acid
NPPV
increase tidal volume by giving the breath an extra push whilst also painting PEEP. This increased breath allows for better CO2 clearance
What happens in T1 resp failure - how does CPAP help
V/Q missmatch
Inadequate oxygenation
- Alveolar collapse (pneumonia
- Fluid in alveoli (L heart failure)
CPAP - maintains minimum airway pressure alveolus held open fluid forced from lung
Eg of 2 causes of t2 resp faulure ?
How does BiPAP help
COPD, Muscular dystrophy
Inadequate ventilation(effect of dead space) -> limited alveolar expansion
at inspiration adds inspiratory pressure (IPAP)
and EPAP at expiration
(further expands lung holds open collapsing increases ventilation airway)
DDx for resp failure - Name a couple
Pneumonia
Atelectasis (collapsed units), pneumothorax
Pulmonary oedema
Thromboembolic disease
Bronchospasm/obstruction, pre-existing, ARDS, increased metabolic demand
Central respiratory depression
Complications of invasive ventilation
VAP (ventilator associated pneum)
VALI (lung injury)
Need sedation and muscle relaxant
Immobility + TED stocking
Oxygen toxicity
What is involved in the pre-op assessment?
History of presenting compaint Surgical, anaesthetic and medical history Systems review Drug history and allergies Social history
ASA SCORE
ASA score
1 - normal
2 - mild systemic disease with no limitation of activity
3 - severe systemic disease with limitation of activity
4 - incapacitating
5
6
NCEPOD - how quickly you have to do surgery
1 - minutes
2 - hours
3 - days
4 - planned
Pre-op drug changes
Steroids - continue
Diuretics - drop say before
ACEi - stop if major surgery or if blood loss anticipated
BBs - always continue
Diabetic meds - sliding scale over night
Warfarin - stop 4 days before and monitor INR
cOCP - supposed to stop 4 weeks before and re-start 2 weeks after
Cancelation reasons
URTI recent MI poor control of drugs poor bloodworm - electrolyte abnormalities inadequate prep - consent, fasting uncontrolled AF
CHECKLIST FOR SAFETY
IDENTITY PROCEDURE CONSENT EQUIPTMENT SITE MARKED ALLERGIES ASPIRATION RISK
Post op
stop vapours
give o2
throat suction
reverse muscle relaxation - neostigmine
Causes of post-op N&V
Patient - female, previous post-op n&v, anxious
Anaesthetic - opioids, NO2, dehydration
Surgery - laparotomy, gynaecology, abdo neuro, ENT, eye
Intra and post op antiemetics
intra - dex, ond
post- cyclizine
wrist thing
Dose of lidocaine
SEs of toxicity and management
3mg/kg, 7 with adrenaline
Toxicity –> numbness of tongue, lightheadedness, visual and auditory disturbances —> go on to really bad ones
Management
Stop injecting LA
A-E
REVERSAL –> intralipid
Differences between spinal and epidural
Spinal
- subdural space
- less amount
- 5-10 min onset
epidural
- into epidural potential space
- larger volume
- 15-30 min headache
Contraindications:
- neuro disease
- hypovolaemia
- anticoagulants
Resp acidosis cause
severe asthma, COPD, hypoventilation
Resp alkalosis cause
hyperventilation, panic attack
Met acidosis cause
DKA, lactic acidosis
Met alkalosis cause
loss of acid (severe vomiting), NG drain
RISK OF FLUIDS
pulmonary oedema
Sx of raised ICP
headache - worse in morning, coughing, bending down
vomiting - without nausea
papilloedema
Cushing’s triad - increased systolic BP, bradycardia, Cheyne-Stoke respiration
