anaesthetics and preoperative care Flashcards
where dose a laryngeal mask sit
in pharynx and aligns to cover the airway
is laryngeal mask suitable for high pressure ventilation
no
what airway dries secretions
tracheostomy
what anaesthetic classification is a brain dead patient
VI
what is propofal mechanism of action
GABA receptor antagonist
is propofol an anti emetic
yes
onset of action of sodium thiopentone
rapid onset
mechanism of action of ketamine
NMDA receptor antagonist
does ketamine cause myocardial depression
slightly
best for those who are haemodynamically unstable
what is done if there is blood loss and chance of infusion is unlikely
group and save
examples of surgery where group and save is done
hysterectomy
appendectomy
thyroidectomy
c section
what is done if blood loss and transfusion is likely
cross match 2 units
blood loss if transfusion can occur
cross match 4-6 units
examples of inhaled general anaesthetics
volatile liquid anaesthetics
- isoflurane
- desflurane
- sevoflurane
nitrous oxide
side effects of volatile liquid anaesthetics
- myocardial depression
- malignant hyperthermia
- halothane is hepatotoxic
when should nitrous oxide be avoided
pneumothorax
examples of IV general anaesthetics
propofol
thiopental
etomidate
ketamine
where is easiest place to insert a central line
femoral
which is preferred for central line
internal jugular
what is preferred route of access in paediatric
intraossesous access
- proximal tibia
size of orange cannula
14g
270ml/min
size of grey cannula
16g
180ml/min
size of green cannula
18g
80ml/min
size of pink cannula
20g
54ml/min
size of blue cannula
22g
33ml/min
can you give lidocaine during acidosis
no as it detaches from protein
drug interactions with lidocaine
beta blocker
ciprofloxacin
phenytoin
can cocaine cross blood brain barrier
yes
when is cocaine mostly used
ENT surgery
how does bupivacaine work
bind to intracellular sodium channels and blocks sodium influx into nerve cells
causes depolarisation
dosage of lignocaine
3mg/kg
what is maximum dose of lignocaine
200mg
why does adrenaline get added to local anaesthetic
to prolong duration of action at site of injection
when is adrenaline contraindicated
patient taking MAOIs or tricyclic antidepressants
what side effect can occur after administration of anaesthetic agents
malignant hyperthermia
characteristics of malignant hyperthermia
hyperpyrexia and muscle rigidity
why does malignant hyperthermia occur
excessive release of calcium form sarcoplasmic reticulum of skeletal muscle
investigations for malignant hyperthermia
CK raised
contracture tests with halothane and caffeine
management of malignant hyperthermia
dnatrolene - prevents calcium release from sarcoplasmic reticulum
examples of muscle relaxants
- suxamethonium
- atrcurium
- vecuronium
- pancuronium
when are nasopharyngeal airways contraindicated
base of skull fractures
complications of naso gastric feeding
aspiration of feed or misplaced tube
what is surgically sited feeding tube
feeding jejunostomy
what can be used for long term feeding
feeding jejunostomy
what is definitive option in patients in whom enteral feeding is contra indicated
total parenteral nutrition
what is long term use of total parenteral nutrition associated with
fatty liver and deranged LFTs
what are early causes of post-op pyrexia
- blood transfusion
- cellulitis
- urinary tract infection
- physiology systemic inflammatory reaction
- pulmonary atelectasis
late causes of post-op pyrexia
- venous thromboembolism
- pneumonia
- wound infection
- anastomotic leak
what is post op ileus
aka paralytic ileus
common complication after surgery involving the bowel results in pseudo-obstruction
features of postoperative ileus
abdominal distension/bloating
abdominal pain
nausea
inability to pass flatus
inability to tolerate an oral diet
fluids before surgery
clear fluids until 2 hours before their operation
when before surgery should you stop no clear fluids
6 hours before
if surgery is long and diabetic will miss a meal or they have poorly controlled diabetes on insulin what is the management
variable rate intravenous insulin infusion
metformin day prior to admission
take as normal
metformin day of morning surgery
take as normal if taken twice a day
if have lunchtime dose - miss this out
metformin day of afternoon surgery
take as normal if taken twice a day
if lunch time dose - miss it
day before surgery sulfonylurea
take as normal
sulfonylurea day of morning surgery
once daily in morning - miss dose
twice daily- omit morning dose
sulfonylurea day of afternoon surgery
taken once daily in morning - omit dose
taken twice daily - omit both doses
DPP IV inhibitor (-gliptins) day prior to surgery
take as normal
DPP IV inhibitor (-gliptins) day of surgery morning or afternoon
take as normal
GLP-1 analogues (-tides) day prior to surgery
take as normal
GLP-1 analogues (-tides) day of surgery morning or afternoon
take as normal
SGLT-2 inhibitors (-flozins) day before surgery
take as normal
SGLT-2 inhibitors (-flozins) day or surgery if morning or afternoon
omit on day of surgery
one daily insulins day prior to surgery
reduce dose by 20%
once daily insulins day of surgery morning or afternoon
reduce dose by 20%
long acting insulin day before surgery
no dose change
long acting insulin day of surgery
halve the usual morning dose evening dose unchanged
mechanism of injury accessory nerve
posterior triangle lymph node biopsy
sciatic nerve mechanism of injury
posterior approach to hip
common peroneal mechanism of injury
legs in Lloyd Davies position
long thoracic nerve mechanism of injury
axillary node clearance
arrhythmia following cardiac surgery can lead to
hypokalaemia
what investigation for rectal anastomotic leaks
gatrograffin enema
features that increase the risk of surgical site infection
- shaving the wound using a razor
- using non iodine impregnated incise drape if one necessary
- tissue hypoxia
- delayed administration of prophylactic antibiotics in tourniquet surgery
perioperative period refers to
temperature management of patients from 1 hour prior to their surgery until 24 hours after the surgery has been completed
risk factors of perioperative hypothermia
- ASA grade 2 or above
- major surgery
- low body weight
- large volumes of unarmed IV infusions
- unwarmed blood transfusion
complication of perioperative hypothermia
- coagulopathy
- prolonged recovery from anaesthesia
- reduced wound healing
- infection
- shivering
combined oral contraceptive pill prior to surgery
stop therapy 4 weeks before
what is a hypertrophic scar
excessive amounts of collagen within a scar
contain nodules
keloid scar
excessive amounts of collagen
pass beyond the boundaries or original injury
do not regress over time may recur
drugs that impair wound healing
- NSAIDs
- steroids
- immunosuppressive agents
- anti neoplastic drugs
lidocaine mechanism of action
blockage of sodium channels disrupting the action potential
what is good anaesthetic agent for haemodynamically unstable patients
ketamine
when is a nasopharyngeal airway contraindicated
base of skull fractures
