Antiemetics/Aspiration Prophylaxis Flashcards
PONV definition
nausea or vomiting within 24 hrs of surgery
2 leading causes of unanticipated hospital admission after outpatient surgery
pain & PONV
what % of patients without prophylaxis have nausea after general anesthesia
40%
what % of high-risk patients have PONV without prophylaxis
80%
risk factors for PONV
female= strongest indicator
nonsmoker
hx of PONV and/or motion sickness
surgical factors for PONV
longer procedures
certain procedures (GYN, laparoscopy, ENT, breast/plastics)
anesthetic factors for PONV
inhalational agents
nitrous
neostigmine
opioids
what is the greatest association of PONV for children
surgical procedure
hernia, tonsila, male genitalia
when does adult PONV risk decrease
may ↓ with age
PONV is associated with
dehydration, electrolyte abnormalities, wound dehiscence, bleeding, airway compromise and UNPLANNED ADMISSIONS and PATIENT DISCOMFORT
scopolamine can prevent
motion-induced nausea and PONV
motion sickness is caused by
stimulation of the vestibular apparatus
what can increase vestibular sensitivity to motion
opioids and morphine
transdermal absorption of scopolamine is beneficial because
patients may have less sedation, cycloplegia, and drying of secretions
zofran mechanism of action
Selective 5-HT3 receptor antagonist in GI tract and Chemoreceptor Trigger Zone
zofran uses
preventative and rescue treatment for N/V
used in chemo
zofran side effects
headaches
diarrhea
zofran should be used carefully in
patients with prolonged QT interval → can lead to torsades
zofran questionable use
obstetrics
zofran dose
4mg IV
zofran duration
4-6 hours
zofran metabolism
extensive hepatic metabolism
Dexamethasone uses
N&V prevention
ENT
traumatic intubations
Dexamethasone mechanism of action
Mechanism is unclear, proposed to centrally inhibit prostaglandin synthesis and control endorphin release
Dexamethasone side effects
genital itching and burning
which drug should absolutely be given after the patient is asleep
Dexamethasone
Dexamethasone caution
diabetics, patients with wound healing issues
Dexamethasone dose
4-12 mg IV
Dexamethasone duration
about 24 hours
promethazine/ phenergan
IV phenergan no longer on US formulaty
promethazine mechanism of action
Phenothiazine, H1 receptor antagonist (antihistamine), Anticholinergic action (motion sickness), D2 antagonist in CTZ
Promethazine is considered
Considered a First-generation H1 receptor antagonist due to sedation potential
promethazine uses
N/V and anxiety
promethazine side effects
Causes sedation, potentiates sedative effects of benzos and opioids (Cesarean delivery), hypotension, extrapyramidal symptoms (Akathisia)
promethazine dose
12.5-25 mg IV diluted and given slowly
promethazine onset
3-5 min
promethazine duration
4-6 hrs
factors associated with complications of aspiration
volume of gastric contents
acidity of the aspirated gastric contents
metoclopramide
Gastrointestinal prokinetic, increases LES tone, enhances response to AcH in upper GI tract to enhance gastric motility and accelerate gastric emptying/reducing gastric volume
metoclopramide antiemetic action is probably due to
antagonism dopamine-agonist effects in the chemoreceptor trigger zone
metoclopramide inhibits ________ receptors within the CNS
dopamine
does metoclopramide cross the blood-brain barrier
yes
metoclopramide side effects
sedation, restlessness, extrapyramidal symptoms
metoclopramide contraindications
bowel obstructions and Parkinson’s, restless leg syndrome, or movement disorders related to dopamine inhibition or depletion
metoclopramide can be used to treat
diabetic gastroparesis, GERD, OB
what med is usually given in preop for aspiration prophylaxis
metoclopramide
does metoclopramide alter gastric fluid pH
no
metoclopramide dose
5-10 mg IV in preop
metoclopramide duration
1-2 hours
metoclopramide onset
1-3 min
rescue drug in PACU
metoclopramide
what med has the potential for neuroleptic malignant syndrome
metoclopramide
hyperthermic toxidromes
may present with overlapping features (hyperthermia, rhabdo, altered mental status/seizures)
famotidine mechanism of action
H2 receptor antagonist
inhibits gastric acid secretion/ fluid volume and raises gastric pH
what drug is given in preop to decrease the risk of pulmonary aspiration in at risk patients
famotidine (pepcid)
famotidine dose
20 mg IV
famotidine onset
30 min - 1 hour
hydroxyzine mechanism of action
Blocks Ach in the vestibular apparatus, blocks H1 receptors in the solitary tract, antihistamine
hydroxyzine uses
N/V
pruritus (pregnancy)
anti anxiety
hydroxyzine side effects
sedation
pain on injection
hydroxyzine dose
25 mg mixed with ephedrine
25 mg IM 20 min before the end of surgery
hydroxyzine caution
in HTN patients and outpatients
