Anti-emetics Flashcards
(121 cards)
What is the most common complication observed in PACU?
PONV
also most common reason (along with pain) for hospitalization following ambulatory surgery
What are the pathways in which antiemetics can prevent and treat PONV?
centrally acting
peripherally acting
combination therapies
What do at risk patients benefit from?
one or more prophylactic measures
What are the types of risk factors for PONV?
surgical, anesthetic, and individual
What are the patient risk factors for PONV?
Female gender (overall strongest predictor), history of PONV or motion sickness, non-smoker, age (risk decreases by 10% per decade), apprehension (r/t swallowed air and abdominal distension), gastroparesis, recent food ingestion
What are the surgical risk factors for PONV?
increased duration of anesthetic/surgery (each 30 min increase in duration increases PONV risk by 60%) surgical type (laparoscopy, ENT, T&A, breast, GU/GYN)
What are the anesthesia risk factors for PONV?
preop administered opioid analgesics, inhalational induction, volatile anesthetic agents, nitrous oxide
What induction agent is found to result in less postoperative vomiting?
Propofol
What are the post-anesthetic related risk factors for PONV?
ambulation, postural hypotension, uncontrolled pain, postoperative opioid administration, early PO intake, lower FiO2 concentration, reversal agents (specifically neostigmine)
According to the SAMBA guidelines when would we give prophylaxis?
Moderate risk- give one or two prophylactic measures
High risk- multiple interventions
The risk factors included in the Apfel score are:
female gender, nonsmoker, history of PONV, postoperative opioids
How can vomiting be triggered directly?
noxious stimuli, toxins, drugs, irritants
How can vomiting be triggered indirectly?
stimulation of the vomiting center in the medulla oblongata
What makes up the vomiting center in the brain?
located in the medulla oblongata: cerebral cortex/thalamus, vestibular apparatus, vagal afferent GI tracts, chemoreceptor trigger zone*** important part of the pathway
What is the goal of combination therapy?
targets multiple receptors, provides rapid onset agent and longer duration of action, benefits patients at high risk, treat with different pharmacological agent class if prophylactic treatment did not work consider combo therapy for certain surgical procedures: gastric, esophageal, plastics, eye, mandibular jaw wiring, increased ICP
What are the receptors involved in the vomiting pathway?
histamine, muscarinic, opioid, dopamine (D2), 5-hydroxytryptamine (serotonin)
What specific serotonin receptor mediates vomiting?
5-HT3 receptor mediates vomiting and is found in GI tract and brain (CTZ & NTS)
How are the effects of 5-HT3 receptor mediated?
via ion channel receptors (gated Na+/K+ channels)
What is the trigger zone of serotonin activated by?
anesthetics and opioids
What does serotonin do to the respiratory system?
causes increased airway resistance
What does serotonin do to the GI system?
release of Ach increases peristalsis
What does serotonin do to the CV system?
powerful vasoconstrictor (except in the heart/skeletal muscle), vasodilation in the heart
What are the serotonin receptor antagonists and what is their action?
ondansetron, palonosetron, dolasetron
inhibit central and peripheral stimulation of 5-HT3 receptors
What are the side effects of serotonin receptor antagonists?
headache, prolonged QT interval