1. Post Op Nausea and Vomiting PONV Issues That Keep Coming Up
Regina Hoefner-Notz MS,RN,CPAN, CPN
Clinical Manager Periop Services CHCO
ASPAN Regional Director: Region 1

2. Objectives Appreciate patient concern and anxiety associated with PONV
Understand the physiology of PONV and treatment modalities
Identify the related issues of PONV
Increase awareness the most recent guidelines created for PONV

4. Definitions
Postoperative Nausea and Vomiting: PONV nausea and/or vomiting that occurs within the first 24 hours after surgery
Early PONV: Occurs within the first 2-6 hours, often in Phase I
Late PONV: Occurs in the 6-24 hour period after surgery
Delayed PDNV: Occurs beyond the 24 hour mark
POV: Reference to pediatric PONV since it is frequently difficult for children to describe nausea

5. Nausea Subjective sensation in back of throat
Conscious cortical activity
May not result in vomiting
Vague I don’t feel good,
Sick to my stomach
No set muscular activity associated with the act of vomiting

6. Vomiting
The forceful expulsion of the gastric contents through the oral and/or nasal cavity
Autonomic reflex directed by the brainstem
Coordinated muscular movements
Physiological changes
Increase HR
Increased RR
Sweating

7. Retching
Objective attempt to vomit
Nonproductive

8. PONV : Patient Concerns
PONV is a huge concern to patients
Patients rank it as the MOST undesirable outcome of surgery, more than pain.
Patients state that PONV is more debilitating than post op pain.

9. PONV : Patient Concerns
The general incident of vomiting is about 30%
The general incident of nausea is about 50%
Subset of high risk patients is about 80%
Peters and Glass 2014

10. PONV : Financial Implications
Can prolong PACU stays
Can prolong Phase II stays
Can lead to unplanned admissions
Every incident of vomiting can prolong stay be approximately 20 minutes

11. PONV : Financial Implications
The cost of treating post op nausea and vomiting in the US has been estimated to cost several hundred million dollars per year.
On average, patients with PONV will cost an additional $ per person
Cost of treating vomiting is 3x higher then the cost of treating nausea

12. PONV : Who Does it Affect?
PONV affects about 1/3 of surgical patients each year which is about 75 million patients.
PONV is one of the strongest predictors of prolonged postoperative stays and unanticipated admissions.
It is still greater then 40% for outpatients that DO receive adequate prophylaxis

13. PONV: Post Op Complications
Can lead to aspiration
Can lead to wound dehiscence
Can lead to bleeding

14. PONV: Post Op Complications
Can lead to dehydration and electrolyte disturbances
Can increase ICP
Can lead to delay of normal functioning

15. Initiating Vomiting Receptors, Chemicals and Organ systems
Complex Interaction of
Receptors,
Chemicals and
Organ systems
Large amount of interplay between the various complex systems
There is actual an area of the brain identified as the vomiting center(see diagram) located in the medulla
Information is transmitted in several different ways through chemical stimulation and a variety of receptors

16. The Vomiting Center “controls” the act of vomiting.
Numerous neuronal pathways converge there to initiate the act of vomiting.
It is not a discreet anatomical site , but rather, represents inter-related neuronal networks.
The vomiting center is activated by the chemoreceptor trigger zone (CTZ) on the floor of the fourth ventricle.

17. Anatomical relationship between different parts of the brain involved with nausea and vomiting.
You can see the brainstem and the relationship here to the vomiting center and also see the CTZ and where that lies.

18. Acetylcholine, Histamine, Serotonin, and Dopamine receptors
Information travels to the vomiting center through the CNS by the use of neurotransmitters
Acetylcholine, Histamine, Serotonin, and Dopamine receptors
The CTZ is abundant with receptors: Receptors for serotonin ( 5-HT3) Histamine , acetylcholine, dopamine and neurokinins just to name the major ones.

19. In the central nervous system (CNS) In the brain stem
Pathophysiological mechanisms causing PONV or the manipulation of neurotransmitters and receptors:
In the central nervous system (CNS)
In the brain stem
In the gastrointestinal tract (GI)
In a simplified explanation you have 3 shots of developing PONV from these 3 different areas
Stimulation of the receptors I just mentioned can activate the vomiting center
Stimulation of the receptors in the vestibular labyrinth can activate the vomiting center via the CTZ
Peripheral input via the GI vagal nerves can stimulate the vomiting center.

20. Inputs Neuronal pathways from Vagal sensory pathways (GI Tract)
Labyrinths
Higher centers of the cortex
Intracranial pressure receptors
Chemoreceptor Trigger Center (CTZ)
Vagal sensory pathways (GI Tract)
Information travels to the vomiting center from higher areas of the CNS (central nervous system)

21. Labyrinth Vestibular
The vestibular apparatus in the middle ear that responds to changes in position of the patient.
Responsible for the nausea and vomiting associated with balance abnormalities.
CNS information from the inner ear or the vestibular apparatus. The neurotransmitters responsible for relaying this information are Acetylcholine/ACh and histamine
Treatment is then accomplished with receptor antagonists
Anticholinergic agents block the binding of Ach (scopolamine and dimenhydrinate)
Diphenhydramine (Benadryl) blocks the action of the NT (neurotransmitter) histamine
One thing I think about is how we are transporting these patients/ how we swing them into bed spaces or turn them around. Initial movements should be slow and purposeful

22. Chemoreceptor Trigger Zone
The chemoreceptor trigger zone in the medulla oblongata responds to chemical changes in the cerebrospinal fluid.
It responds to the peripheral nerve pathways, which are stimulated by chemical changes in the blood and viscera.

23. Anatomical relationship between different parts of the brain involved with nausea and vomiting.
You can see the brainstem and the relationship here to the vomiting center and also see the CTZ and where that lies.

24. Chemoreceptor Trigger Zone (CTZ)
Close association with CSF and a large blood supply.
Not protected by the blood brain barrier.
Detects the presence of drugs and toxins. (severe N&V)
CTZ works through the 5-HT3 and Dopamine2 receptors
If you go back to the picture of where it sits it is out of the blood /brain barrier area
seems to work well by utilizing the 5_HT and D2 antagonists
5_HT Ondansetron, etc
D2: droperidol, metoclopramide

25. GI tract Stimulation via the Vagus Nerve
GI distention and manipulation can stimulate receptors from the wall of the gut, which then releases serotonin.
The presence of foreign chemicals or blood can also release serotonin.
Next slide

26. (5-HT3) receptor, such as ondansetron.
This calls for the administration of a selective serotonin antagonist at the
5-hydroxytryptamine3
(5-HT3) receptor, such as ondansetron.
Decreases the visceral information carried from the GI tract to the Vomiting Center.
The administration of selective serotonin antagonists at the 5-HT receptor (5-hydroxytryptamine) decreases the VISCERAL information carried from the GI tract to he vomiting center
Example: Ondansetron

27. PONV Guidelines Last guidelines developed were from 2003 and 2007
Society for Ambulatory Anesthesiology conducted literature reviews yielding hundreds of publications since 2007
Utilized a multidisciplinary approach to re-evaluate this issue and treatment
Why do we need theses? There are other guidelines but we are constantly learning new information
ASA guidelines were too broad because they were looking at all scope of service
Several written is different languages.
This new guidelines contains
New antiemetic's (neurokinin-1 receptors)
All members review since 2007, working in groups to weigh evidence
Majority ruled but was stated it was not unanamous

28. Goals of the Guidelines
Determine optimal dosage and timing of antiemetic prophylaxis
Evaluate cost effectiveness strategies
Create an algorithm to identify patients at risk and best treatment options
Propose future research
P. Glass 2014

29. Goals of the Guidelines
Understand who is at risk for PONV in adults and POV (children)
Establish factors that reduce the baseline risks of PONV
Determine the most effective antiemetic single/combo therapies pharmacological and non-pharmacological
Determine the best approach to treatment with or without prophylaxis
P. Glass 2014

30. Highest Indicators for PONV
Female gender
History of PONV
Non-smoking status
History of motion sickness
Use of opioids in PACU
Anesthesia predictors:
Uses of volatile agents
Duration of anesthesia
-Recent work and meta-analysis reaffirms indicators that have been previously identified, but there seems to be a different order of importance
Female gender, still strongest indicator
History of PONV
Not so much opioid usage in the OR but definitely PACU

31. Identifying Patients at Risk New information
Younger = significant risk (less than 50 yrs.)
Type of surgery: cholecystectomy, gynecological, and laparoscopic surgery associated with a higher risk of PONV
Intraoperative opioids has weak evidence for causing increase PONV
-Recent studies indicate that younger than the age of 50 can increase your likelihood for developing PONV
-Type of surgery is still debated: but higher confidence interval: cholecystectomy, gynecological, and laparoscopic surgery associated with a higher risk of PONV when compared with general surgery as a reference point.
-Intraoperative opioids has weak evidence for causing increase PONV /no difference among the various opioids

32. Highest Indicators for POV in Pediatrics
Surgery greater than 30 minutes
Age greater than 3 years
Strabismus surgery
History of POV
Relative with PONV

33. Age. Children are two times more likely to develop POV than adults
Age.  Children are two times more likely to develop POV than adults.  POV is low in very young children, increases up to the age of 5 and is highest in children between the ages of 6 and 16 years.

34. Low to No Evidence BMI Anxiety Supplemental O2 Perioperative fasting
Migraines
There is no evidence to support adding additional oxygen can prevent the initiation of PONV. New information for me.
The previous guidelines suggested that the length of fasting was an indicator, but this is not added as and indicator since there is not strong evidence to support this

35. Reduce Baseline Risks The avoidance of general anesthesia
Preferential use of propofol infusions
Avoidance of Nitrous Oxide
Avoidance of volatile anesthetics
Minimize perioperative opioid usage
Adequate hydration
Guideline #2
Using regional anesthesia 9x less likely to cause PONV in adults and children
Using propofol for induction and maintenance decreases early PONV (1st 6 hours) Utilizing combo of propofol, TIVA, air or O2 could reduce PONV by 25%
Recommended usage of non opioid drugs but still making pain management a priority
NSAIDS, cyclooxygenase-2 inhibitors (cox 2 inhibitors) A selective inhibitor of COX-2 (SC-58125) inhibited edema at the inflammatory site and was analgesic but had no effect on PG production in the stomach and did not cause gastric toxicity. These data suggest that selective inhibition of COX-2 may produce superior anti-inflammatory drugs with substantial safety advantages over existing NSAIDs.

36. Reduce Baseline Risks
New information from review of randomized controlled trials (RCT): “supplemental oxygen had no effect on nausea or vomiting”
This new guideline no longer recommends supplemental O2 for prevention of PONV
Orhan-Sungur, et all 2008

37. Reduce Baseline Risks
Pediatric patient respond to a decrease in baseline risk factors
Utilizing blocks decreases opioid usage
Strabismus patient receiving peribulbar blocks during repairs had decrease emesis from control groups (Gupta et all 2007)
Utilizing propofol and dexamethasone together decreases emesis in T&As (Erdem, et all 2009)
Recent studies indicate that decreasing the baseline risk factors in pediatric population also decrease their incidence of POV
Catch 22, trying to get them into the OR and inserting blocks.
Children receiving intraoperative propofol in sub hypnotic doses combined with dexamethasone had less emesis then those receiving dex alone
Cardwell et all(2013) concluded NSAIDS do not increase bleeding after T&As but less emesis was noted in 928 children

38. Administer PONV Prophylaxis Using 1&2 Interventions
Recommended PONV medications include:
5-hydroxytryptamines receptor antagonists (5-HT3)
Neurokinin-1 receptor antagonists (NK-1)
Corticosteroids
Butyrophenones
Antihistamines
Anticholinergics
Guideline#3
5-HT3 receptors antag. (ondansetron, dolasetron, granisetron, tropisetron, ramosetron, and palonosetron
Neurokinin-1 receptor antagonists (NK-1) (aprepitant, casopitant, and rolapitant)
Corticosteroids (dexamethasone and methylprednisolone )
Butyrophenones: (droperidol and haloperidol)
Antihistamines: (dimenhydrinate and meclizine)
Anticholinergic: transdermal scopalamine

39. Serotonin (5-HT3) Antagonists
Ondansetron (Zofran)
Granisetron (Kytril)
Tropisetron (Navoban)
Palonosetron 2nd generation 5-HT
Dolesteron (anzement)no longer marketed in the US due to prolong QT and possible torsades de pointe
No significant side effects. May cause HA, dizziness or diarrhea.
More effective for vomiting then for nausea
Favorable side effect profile
All but palonosetron effect the QT segment
2012 FDA: Ondansetron even with chemo should not exceed 16mg/24 hours
32mg dose off the market
4mg post op still recommended

40. Neurokinin-1 receptor antagonists (NK-1)
Newly developed for severe nausea and vomiting
Substance P belongs to the neurokinin family of neurotransmitters
The medication, Aprepitant, blocks this neurotransmitter
Oral administration
Works up to 24 hours
neurokinin 1 receptor (NK1R) or substance P receptor (SPR) is a G protein coupled receptor found in the central nervous system and peripheral nervous system. The endogenous ligand for this receptor is Substance P, although it has some affinity for other tachykinins.
Should be given 3 hours prior to anesthesia

41. Corticosteroids Dexamethasone (decadron)
Recommended to be given at the beginning of induction for patients with increase risk of PONV
Low risk, can be given at end of surgery
Can cause spikes in serum glucose. Use cautiously with patients with labile blood sugars
Can decrease use of overall opioid medications/pain relief functionality
No definitive data on increasing risk of postoperative infection
No proposed receptor site
Single dose well tolerated
*vaginal itching or anal irritation with IV bolus
his drug is not fully understood. It does have some anti-emetic properties, but is more used to enhance the efficacy of other anti-emetic drugs.
Methylprednisolone 40mg (Medrol) is effective in the prevention of late N&V

42. Dopamine (D2) receptor antagonist
Phenothiazine: Metoclopramide (Reglan)
Butyrophenones: Droperidol (Inapsine)
These drugs can cause prolonged emergence, hypotension, or extrapyramidal reactions.
Metoclopramide at 10 mg is a weak anti emetic and generally is not effective in decreasing N&V Increase doses might help but also increases the chance of extrapyramidal reaction's
Droperidol is superior for N&V when compared to Reglan but has stopped being used due to the black box warning. Studies indicate it does not have a higher incident of QT prolongation then Ondansetron and when used together provide great coverage for N&V
Many European countries are using it.

43. Antihistamines Promethazine (phenergan) Diphenhydramine (benadryl)
Prochlorperazine (compazine)
Hydroxine (atarax)
Down side includes drowsiness, dry mouth, possible dizziness, some potentiate narcotics and barbiturates.

44. Anticholinergics Scopolamine patch Glycopyrrate (robinul) Atropine
Dramamine
Sometimes more responsive to vestibular impulses and motion sickness.
Anticholinergic agents will block the binding of acetylcholine (ACh)

45. Alternative Measures ?
Aroma therapy: No significant evidenced based data at this time
“QueaseEase” 4 essential oils
Spearmint, peppermint, ginger and lavender,
Deep Breathing :Maybe can’t hurt
Gastric Emptying: no information
Gastric Decompression: does not help
Some Acupressure bands: P6 studies
Some good information from St. Jude’s hospital on queaze-ease
Isopropyl alcohol does not help with N&V
Music therapy does not help

46. Management Algorithm:2014
Adult risk factors
Pediatric risk factors
Patient preference
Cost effectiveness
Reducing baseline risk
Low: wait and see
Medium: Pick 1-2 interventions
High: Greater than 2 interventions
Not every patient is necessarily a candidate for medication to prevent PONV

47. “Just because its there doesn’t mean you have to use it”
Need to identify the subset of patients that might require prophylaxis
Generic drugs get the job done
Ondansetron 4mg, droperidol 1.25mg and dexamethasone 4mg were equally effective and independently reduced PONV risk by 25% (in adults)
Apfel et all, 2004

48. Risk Factor Assessment
Risk Level
Low Risk
Moderate
Risk
Severe
Very
% chance of PONV
10-20%
40 %
60 %
80 %
# of prophylactic interventions to consider 1 2
3 or more

49. Rescue Treatment
Antiemetic strategies implemented AFTER the onset of symptoms
Administer different medication then prophylactic one
Check for other reasons such as hypotension
? isopropyl alcohol: not effective prophylactic but seems to help afterwards
Which should include adequate hydration
Other causes should be ruled out such as hypotension.
Any medication used for prophylaxis should not be used for Rescue treatment. The rescue medication should have the ability to block a different receptor.
Dehydration abnormalities and fluid imbalance may lead to stimulating of the CTZ resulting in PONV. Patients at risk (pediatric patients) need to have a return to baseline fluid. Not necessarily PO but giving IV hydration and finding out the NPO status and understanding how much fluid might be needed to get that patient back to baseline. And possibly beyond.
There was no difference noted between the use of crystalloid vs colloid in surgeries where there were not significant fluid shifts.

50. Nursing Considerations
Pre op Information
Thorough history
Risk factors identified
Pre administration of anti-emetics

51. Nursing Considerations
First and foremost - airway management, preventing aspiration, providing high flow O2
Positioning- no sudden movements or transfers
Hydration- checking fluid deficits and rehydrating appropriately.
Calming reassurance to decrease anxiety.
Deep breathing to optimize oxygenation.
Possible use of aroma therapy with inhalation of isopropyl alcohol vapors.
Pain medication used judiciously, opioids verses NSAID’s.
Medicate as necessary per MD order, evaluating previous medications and their efficacy.

52. Patient Education How to manage fluids or foods
How many diapers or how often child urinated during the day
Should some medications be taken with food?
Comfort measures specific for that child
When to call Primary physician
Talking to parents about keeping a child hydrated. Drinking, and not worrying about eating.
How many diapers did they have today?
Are they peeing.
Don’t give things that you don’t want to clean up
Side effects of opioids/ also constipation
P6 Study in jopan

53. The cost of treating prolonged PONV can be devastating to the patient, family and institution.
Understanding causality and treatment options are essential for optimal post operative care. .