GI (pt 5/5) PONV cont. Flashcards
What is the MOA for Phenothiazines for N/V prevention?
Block dopamine and muscarinic receptors and depending on their structure anti-histamine effects.
What are the side effects associated with Phenothiazines?
-Sedation, dry mouth – due to their antihistamine activity (not rly used in anesthesia because of sedation)
-Dystonic reactions- dopamine antagonism, decrease BP
-Deep IM inj., good working IV- tissue necrosis, gangrene risk (may want to dilute, make sure IV is working well)
What are the example drugs of Phenothiazines used for N/V Prevention?
Prochlorperazine (Compazine)
Promethazine (Phenergan)
Thiethylperazine (Torecan)
Antipsychotic agents used for their antiemetic properties.
What is the MOA of Butyrophenones (Droperidol)?
-Antipsychotic with antiemetic properties
-Block central dopaminergic receptors
What are the side effects associated with Butyrophenones (Droperidol)?
-Sedation, dystonic reactions
-CNS effects – hallucinations, post-anesthesia delirium, depression, nightmares, decreased seizure threshold
-Hypotension – especially with epidural or spinal anesthesia
-Black Box Warning – may prolong QT interval 🡪 ventricular tachycardia including torsades de pointes
What patients should you NOT use Droperidol (Butyrophenones) with? (Blue Box!!)
DO NOT use with QT prolongation & only used in patients who have not responded to alternative antiemetic agents.
What is the MOA for Substituted Benzamides (Metoclopramide and Trimethobenzamide) for N/V?
Block Dopamine Receptors in CTZ
What are the adverse effects associated with Substituted Benzamides (Metoclopramide and Trimethobenzamide) for N/V?
Extrapyramidal – restlessness, dystonias, & parkinsonian symptoms
What are the two First generation histamine H1 Antagonists with significant anticholinergic properties used for N/V?
Diphenhydramine (Benadryl ) & Dimenhydrinate (Dramamine)
What is an H1 Antihistaminic agent with minimal anticholinergic properties used for N/V?
Meclizine
What is Hyoscine Hydrobromide (Scopolamine)?
A Prototypical muscarinic receptor antagonist.
-Transdermal patch needs to be placed night before surgery or 2 hours before surgery for best effect.
-Best agent for the prevention of motion sickness.
What is the MOA for H1 Antihistamines and Anticholinergic Drugs in prevention of N/V?
Interrupt visceral afferent pathways in the GI tract.
-Weak antiemetic activity – better for simple N&V
-Useful for the prevention or treatment of motion sickness (Scopolamine)
What are the side effects associated with H1 Antihistamines and Anticholinergic Drugs? (Limit their use for N/V)
Dizziness
Sedation
Confusion
Dry mouth
Urinary retention
What Benzodiazepines can be used before the initiation of chemotherapy to reduce anticipatory vomiting or vomiting caused by anxiety?
Lorazepam (Ativan) or Diazepam (Valium)
Which benzodiazepine, when given 30 min before the end of surgery, is shown to be as effective as Zofran?
Midazolam (however, risk of sedation)
What are the example drugs of the Cannabinoids that are used for N/V prevention?
Dronabinol (Marinol) & Nabilone (Cesamet)
What are the medical uses of the Cannabinoids?
-Stimulate appetite
-Prevent chemotherapy-induced nausea and vomiting
What is the combo therapy used with Cannabinoids?
Combotherapy with phenothiazines: Synergistic antiemetic action and appears to attenuate the adverse effects of both agents
What are the adverse effects of the Cannabinoids?
High incidence of SEs associated with use.
-Euphoria
-Dysphoria
-Sedation
-Hallucinations
-Dry mouth
-Autonomic effects: Tachycardia & orthostatic hypotension
-May potentiate the clinical effects of other psychoactive agents
What is Propofol?
A sedative/hypnotic that has anti-emetic properties in subclinical doses.
-Used in TIVA
-Decreases risk of PONV in first 6 hrs
-Not effective for PDNV
PONV effects ___ - ___% of patients, and ___-___% of high risk patients.
Effects 20% - 30% of patients, and 70%-80% of high risk patients.
The Incidence of vomiting is __ nausea.
The Incidence of vomiting is < nausea.
What are the Inhalation Agents with risk of producing PONV, listed from greatest to least?
-Halothane
-Enflurane
-Isoflurane
-Desflurane
-Sevoflurane
What is the strongest predictor of PONV?
The use of volatile anesthetics.
-Sevo causes the least amount of PONV.
Propofol decreases _______, but not _____.
Propofol decreases PONV, but not PDNV.
Why does length of procedure increase risk of PONV?
Longer procedures = longer exposure to inhalational anesthetics and opioids
______ use of N2O in longer cases (>30 min)
Decrease use of N2O in longer cases (>30 min).
The greatest risk of PONV is ___-___ hours following surgery.
The greatest risk of PONV is 2-6 hours following surgery.
N2O > ____ hour increases the risk of PONV.
N2O > 1 hour increases the risk of PONV.
What are the risk factors for PONV in adults?
-Female sex
-History of PONV or motion sickness
-Nonsmoking
-Younger age
-General vs Regional Anesthesia
-Use of Volatile anesthetics & N2O
-Use of postop opioids
-Duration of anesthesia >1 hr
-Type of surgery (Cholecystectomy, Laparoscopic, gynecological)
What surgical procedures are associated with an increased incidence of PONV in adults?
-Laparoscopy
-Cholecystectomy
-Gynecological
-D&C
-Tooth extraction
-Head & Neck surgery
-GI surgery
Why are ENT surgeries associated with a higher incidence of PONV?
Especially occurs with Middle Ear Surgeries.
-Accumulation of blood in the posterior oropharynx, which may drain into the stomach or be swallowed during the post-op period can cause PONV
-Pack the back of the throat
-OGT at the end of the procedure to remove gastric contents/blood
What surgical procedures are associated with an increased incidence of PONV in children?
-Tonsillectomy and Adenoidectomy
-Orchiopexy
-Middle ear surgery
-Otoplasty
-Strabismus repair
Should you use Propofol in children with Strabismus?
In children with Strabismus, propofol can increase the oculocardiac reflex in these kids (severe bradycardia). Give a little glyco if using TIVA during these surgeries.
What is the Apfel Scale?
A risk score for N/V.
What are the risk factors for PDNV?
-Female
-Hx of PONV
-Age < 50
-Use of opioids in PACU
-nausea in PACU
-Surgery >60 minutes
What is a Low Risk Classification for PONV?
0-1 Risk Factors present
What is a Mild to Moderate Risk Classification for PONV?
20-40% risk of developing PONV
1-2 risk factors present
What is a Moderate to High Risk Classification for PONV?
40-80% risk of developing PONV
3-4 risk factors present
What is a Very High Risk Classification for PONV?
> 80% risk of developing PONV
3-4 risk factors present
Management of N/V should originate from a _____________ rather than a _________approach, especially with patients identified as high risk.
Management of N/V should originate from a prophylactic rather than a therapeutic approach, especially with patients identified as high risk.
See Table 55.4 – Apfel’s Risk Assessment Tool
Yes
For 1-2 Risk factors, give __ anti-emetics.
2 anti-emetics.
For >2 Risk factors, give __ anti-emetics
3-4 anti-emetics.
What classes of drugs can be used for N/V Prophylaxis?
-5HT3 Receptor antagonists
-Corticosteroids
-Antihistamines
-Dopamine Antagonists
-Propofol
-NK-1 Receptor Antagonists
-Anticholinergics
-Acupuncture
Basically, give everyone Decadron and Zofran prophylactically (unless c/i like in brittle diabetics).
What drugs should you use for rescue tx of N/V?
A drug from a different class than the prophylactic drug.
What are risk factors for n/v in pediatrics?
-Age >3 years
-Hx of POV/PONV/motion sickness (or family hx)
-Post-pubertal female
-Surgery >30 min
-Volatile Anesthetics
-Anticholinesterases
-Postop opioids
What are multimodal anesthetic techniques to decrease PONV?
-Prophylactic IV acetaminophen (before the onset of pain)
-Perioperative NSAIDs and Cox 2 inhibitors (caution- may cause anastomosis leakage)
-Ketamine intra op but less so then Acetaminophen and NSAIDS
-Alpha 2 agonists like Dexmedetomidine and clonidine to decrease post op pain, opioid consumption and PONV. Prophalactic .5/ug/kg deduced pain at 1 hour post op and POD 1-3 pt were faster to get back to ADL’s.
-Epidural, TAP blocks, continuous wound infiltration with local
-TIVA and volatile were the same when you add a 5HT3 blocker and droperidol
-Propofol at subhypnotic doses with anti-emetic also decreased PONV
-PONV lower with suggammadex then with Neostigmine
-Lidocaine infusion with abd laporoscopic procedures was lower with lido infusion
Patients who are at a higher risk for N/V, avoid ____ and give ____ instead with reversal.
Avoid neostigmine and give Sugammadex instead.
What are anesthetic techniques to reduce the risk of PONV?
-Avoid GA (use RA)
-Use propofol
-Avoid N2O in surgery > 1 hr
-Avoid Volatile anesthetics
-Minimize opioids
-Adequate hydration
-Avoid Neostigmine and give Sugammadex
What is the 3 step approach to the management of PONV/PDNV?
1) Risk assessment for prevention
2) Adjustment of preventive measures used
-May include a modification of the anesthesia technique
3) Follow-up with use of rescue treatment immediately by targeting mechanisms that have not yet been tried
-May include non-pharmacologic methods
Which antiemetics do you give at induction?
-Aprepitant
-Dexamethasone
-Palonosetron
-Rolapitant
Which antiemetics do you give at the end of surgery?
-Dolasetron
-Droperidol
-Granisetron
-Ondansetron
-Ramosetron
-Tropisetron
Which anti-emetic do you give the prior evening or 2 hr before surgery?
Scopolamine
What are non-pharmacologic anti-emetic mechanisms?
-Acupuncture
-Transcutaneous electrical nerve stimulation (TENS): Place it over the acupuncture point of the wrist
-Acupoint stimulation
-Acupressure
-P6 stimulation
-Korean hand acupoints
-Controlled breathing
-Isopropyl alcohol
How does P6 Stimulation help with anti-emetic?
-Decreases N&V and need for rescue antiemetics
-Similar to using Zofran, droperidol and reglan
-Adults and Children alike
-Timing doesn’t matter before/after induction
-10 different acupuncture modalities
How does Neuromuscular stimulation of the median nerve have anti-emetic effects?
-Also reduces incidence of PONV early on
-Better when use tetanic stimulation
What are other non-pharmacologic anti-emetic prophylaxis?
-IV fluid therapy-no difference in colloid vs crystalloid
-Low dose Narcan infusion
-Noni-fruit -600mg
-Ginger 1gm 1 hour before induction
