This document discusses postoperative nausea and vomiting (PONV). It begins by explaining why PONV is an important issue, noting the high incidence rates and negative patient experiences and outcomes associated with it. It then covers the physiology and classification of PONV. Major sections discuss risk stratification and identification of independent risk factors, as well as pharmacological and non-pharmacological prophylaxis and treatment options. Drug therapies covered include 5-HT3 receptor antagonists, NK-1 receptor antagonists, corticosteroids, butyrophenones, and other classes. Non-drug approaches like acupuncture, hydration, and hypnosis are also mentioned.

1. POST OPERATIVE
NAUSEA & VOMITING
SPEAKER :- DR. RAMESH V
MODERATOR :- PROF. DR. KH.MANIRAM SINGH

2. PONV
Why is it Important?
 Patients rank PONV as one of the most
unpleasant memories associated with their
hospital stay.
 Patient satisfaction with their anaesthetic is highly
linked to their experience (or lack of ) of PONV. In
surveys, many state they prefer to experience pain
than N&V.
 When severe it can lead to increased length of
hospital stay, increased bleeding, incisional
hernias and even life threatening aspiration
pneumonia.

 Despite decades of progress in surgical and
anaesthetic techniques, effective prevention and

3. PONV
Incidence!!!
 A very common problem in the ambulatory surgery patient
population, occurring in an estimated 35% of all patients. If high-risk
patients are considered as a separate group, then as much as 70%
of these patients will experience PONV.
 Before the 1960s, when older inhalational anesthetic agents such as
ether and cyclopropane were widely used, the incidence of vomiting
in general population was as high as 60%.

4. What is PONV?
● Nausea
● Retching
● Vomiting

5. Classification
 Early PONV – within 6 hours of emergence
from anaesthesia
 Late PONV -- 6 to 24 hours after the
procedure

6. Physiology of PONV

8. Risk Stratification
 Postoperative nausea and vomiting is a
multifactorial entity, comprising patient, surgical,
and anesthetic factors.
 Due to the cost of pharmacological Tx of
emesis, risk stratification is important.
 By focusing attention (and resources) on those
groups of patients most likely to develop PONV,
the overall cost of dealing with PONV is
reduced.
 A number of studies have looked into PONV risk
factors and risk stratification.

9. Risk Stratification
Patient related independent predictors
 Female>male (x3)
Incidence increases during menstruation and decreases after the
menopause. After 70 years of age, both sexes are equally affected.
 Non smokers ( 1.8 times more)
 Obese
(suggested but no strong evidence).
 Age.
POV in under 2yr olds is rare. From >3yrs to puberty, risk is higher than
adults.
 Previous history of PONV/motion sickness
 Early ambulation, early postoperative eating and drinking.
 Anxiety

10. Risk Stratification
Surgery related independent predictors
 Intra-abdominal-laparoscopic
 Intracranial, middle ear
 Squint surgery
The highest PONV risk surgery in children
 Gynaecological
Esp ovarian
 ENT
Especially T & As (? due to blood in upper GIT)
 Prolonged surgery( each 30 min increase – risk by 60%
 Significant surgical pain

11. Risk Stratification
Anaesthesia related independent riskfactors
 Opioids
Well known for emetogenic potential but remember untreated pain can also
be emetogenic
 Sympathomimetics
 Inhalational agents
Isoflurane++, Etomidate, ketamine, methohexitone. Propofol considered
one of the least emetogenic
 Nitrous oxide
 Prolonged anaesthesia
 Spinal anaesthesia (blocks above T5), hypotension.
 Intraoperative & Preoperative dehydration
 Gastric dilatation
Eg aggressive mask ventilation

12. Risk Stratification
Pathology
 Intestinal obstruction
 Metabolic, e.g. hypoglycaemia
 Hypoxia
 Uraemia

13. Quick Risk Factor Chart
Apfel’s simplified score for adults

14. Eberhart’s simplified score for children
 Post operative vomiting score (POV)

15. Post-discharge nausea and vomiting
“PDNV defined from 24 h post-
discharge upto 72h has an incidence of upto
55%”
Ambulatory surgery
Chandrakantan A et al. Multimodal therapies for ponv. Br J Aneasth
2011;107:I 27-40

16. Apfel’s simplified score for PDNV

18. Prophylaxis and Treatment of
PONV
I. Valid Assessment of patient’s risks
II. Reduce the baseline risk factors
III. Pharmacological therapy with single/
combined administration of antiemetics
IV. Non Pharmocological therapy

19. Risk Stratification
Low Riskof PONV pts
 No prophylaxis or minimal prophylaxis is likely
the best choice
Moderate Riskof PONV pts
 Prophylaxis followed by aggressive treatment
if nausea and vomiting develop.

20. High Risk of PONV ptsHigh Risk of PONV pts
Aggressive prophylaxis + treatment. Expensive but becomes cost-effective whenAggressive prophylaxis + treatment. Expensive but becomes cost-effective when
the issues of patients satisfaction and avoidance of unplanned admission arethe issues of patients satisfaction and avoidance of unplanned admission are
considered. Multi-modal therapy widely accepted as providing the best resultsconsidered. Multi-modal therapy widely accepted as providing the best results
Risk Stratification

21. Reduce Risk Factors
Avoid General Anesthesia
Avoid Volatiles
Utilize Propofol Infusions
Avoid Nitrous Oxide
Minimize Perioperative Opioids
Provide Adequate Hydration

22. Regional vs General
Aneasthesia
 Patients who were randomized to two groups
 receive a peripheral nerve block had a more
than fourfold lower incidence of nausea than
those receiving a generalanesthetic regimen
(6.8% versus 30%).

24. Servizio di Anestesia e Rianimazione Ospedale di
Supplemental Oxygen
30 % Oxygen 80% Oxygen Ondansetron
Patients (female) 80 79 71
0-6 hr PONV (%) 36 20 27
nausea (%) 35 20 27
vomiting (%) 19 9 14
6-24 hr PONV (%) 13 4 6
nausea (%) 11 4 6
vomiting (%) 9 4 1
0-24 hr PONV (%) 44 22* 30
nausea (%) 41 22* 30
vomiting (%) 26 10* 15
Goll et al. Anesth Analg 2001;92:112-117

25. PONV: Drug Therapies
5-HT3 Receptor Antagonists
o Ondansetron, Dolasetron,
Palonosetron,
Granisetron,Tropisetron
NK-1- Receptor Antagonist
o Aprepitant (Emend)
Corticosteroids
o Dexamethasone
Butyrophenones
o Droperidol, Haloperidol
Antihistamines
Promethazine,cyclizine,Dimenhydrinate
Anticholinergics
o Transdermal Scopolamine
Dopamine antagonists
o Metoclopramide,alizapride,prochlorp
erazine
Propofol
Gabapentin
Midazolam
Alpha 2 agonists

26. Figure 6 summarises the sites of actions of the drugs that influence PONV.

27. Recommended Dosages and Timing

28. 5HT3 Antagonists
5HT3 receptors – entero chromaffin cells of
S.I and Brain
ONDENSETRON
FDA Dose - 4 mg
Plasma ½ life – 3hours ( at the end of surgery)
Reduce the risk by 26%
Complications – Headache,Nausea,Slight
prolongation of QT ,allergic reaction ,
bronchospasm

29. 5HT3 Antagonists
DOLASETRON
FDA Dose – 12-50 mg
IV-12.5 mg
Oral- 25- 30mg
Plasma ½ life – 7hours( at induction)
GRANISETRON
FDA Dose – 1mg( 20-40micg/kg)
Plasma ½ life – 9hours(at induction)

30. 5HT3 Antagonists
TROPISETRON
It s an indole acetic acid ester of tropine
FDA Dose – 2mg
Plasma ½ life – 7hours
PALANOSETRON
Most effective antiemetic in this group with NK1
antagonism
FDA Dose – 0.075mg
Reduce the risk by 30% with ½ life of 40 hours
Most useful in PDNV

31. Pharmacology
Dexamethasone
MOA – Inhibition of NTS
Central inhibition of prostaglandins
FDA Dose – 10mg
Slower in onset
Administer at the induction
Complication – Perioperative hyperglycemia in
DM and obese patients
.

32. Scopolamine
Transdermal formulations
FDA Dose – 1.5 mg(5micg/hr) with 72 hours ½
life
Night before surgery(44%) or morning(59%)
Most useful in PDNV
Complications- visual disturbances(24 to
48hrs), central anticholinergic syndrome, dry
mouth,tachycardia, dry skin, urinary retention
Anticholinergics

33. Pharmacology
 Droperidol (butyrophenone)
For many years, droperidol (in very small
doses) was very popular in any strategy against
PONV. Droperidol is very effective in small
doses (0.625-1.25mg) for the prevention and
treatment of PONV, Plasma ½ life of 3 hours.
Risk reduced by 26%
Unfortunatey its use has declined after its
association with rare fatal arrythmias (although
at higher doses)
FDA has given Black box warning
Contraindicated in suspected QT prolongation

34. Dopamine Antagonists
 Metoclopramide
 FDA Dose- 10 mg (0.2-0.5mg/kg)
 MOA- D2 receptor antagonist both central and
peripheral
 Complications – EPS, hyopotension,
tachycardia
 Contraindicated in parkinson’s disease,
restless leg syndrome

35. NK1 Antagonists
 Aprepitant
 NK1 receptors- GIT
 Substance P in vagal afferents
 FDA Dose- 40 mg orally (at induction)
 Risk reduced by 69%
 High cost

37. Mirtazapine
Mirtazapine is a noradrenergic and specific
serotonergic
antidepressant.
Mirtazapine 30 mg per os plus dexamethasone
8 mg reduces the incidence of late PONV by
>50% compared with dexamethasone8 mg
alone.

38. Gabapentin
Gabapentin doses of 600 mg per os given 2
hours before surgery effectively decreases
PONV.
Gabapentin Given 1 hoursbefore surgery,
gabapentin 800 mg per os is as effective as
dexamethasone 8 mg IV, and the combination
is better than either drug alone

39. Midazolam
 Midazolam 2 mg when administered
30minutes before the end of surgery was as
effective against PONV as ondensetron 4 mg.

40. Combination Therapy
 If a dose of a single agent is ineffective,
additional dose of same agent is unlikely to
increase efficacy. In fact it is likely to
increase the riskof side effects

41. Contd..
 Consensus Guidelines for combination therapy

42. Rescue Treatment
 5HT3 antagonist – ondensetron is the first line
therapy for PONV
 Minimally effective dose for treatment is only
one quarter of the dose needed for
prophylaxis
 Other drugs:-
metaclopromide,Droperidol,Dexamethasone,P
ropofol
 It is preferable to administer drugs that have
not been used previously

43. Algorithm for Management of
PONV

44. Non Pharmacological Therapy
 Non-pharmacological Treatments:
 P6 Acupuncture and acupressure
 Hydration
 20ml/kg of crystalloid
 Hypnosis/therapeutic suggestion

45. P6 and Median Nerve Stimulation
Fre y UH, Funk M, Lo hle in C, Pe te rs J. P6 acustim ulatio n e ffe ctive ly de cre ase s po sto pe rative nause a
and vo m iting in hig h-risk patie nts unde rg o ing a laparo sco pic cho le cyse cto m y. Acta Anae ste sio l
Scand 20 0 9 ; 1 0 2: 6 20 -5
Meta-analysis
• 40 articles
• 4,858 subjects
Efficacy
• similar to ondansetron and
droperidol
Timing

46. Intravenous Fluid Therapy
0
5
10
15
20
30 min 60 min DIS Day 1
Time
Incidence%
Low Infusion High Infusion
)
*
Yogendran S, et al. Anesth Analg 1995;80:682-686
High Infusion = 20
ml/kg
Low Infusion = 2
ml/kg
Incidence of Postop Nausea

47. Contd..
 A meta-analysis study on preoperative IV fluid
therapy demonstrated that can be effective as
antiemetic therapy to reduce PONV
 By alleviating dehydration and organ
hypoperfusion

48. In Summary..
STEPONE
Identify Pts at risk
Attempt to stratify in low, moderate and high risk
group

49. In Summary..
STEPTWO
Reduce Baseline RiskFactors
 Use Regional anaesthesia when possible
 Use propofol forinduction and maintenance
 Use intra-operative supplemental oxygen
 Use hydration
 Avoid Nitrous oxide, volatiles
 Minimise opiod use
 Minimise neostigmine use

50. In Summary..
STEPTHREE
Prophylaxis formoderate & high
risk
 Multimodal drug prophylaxis

51. In Summary..
STEPFOUR
Aggressively Tx PONV
 Forpts where prophylaxis failed orwas not used
 Ondansetron as first line Tx
 Add additional agents if PONV continues

52. Remember…
 PONV is one of the most distressing aspects of
an anaesthetic fora patient.
 Be aware of RiskFactors and give pre-emptive
prophylaxis if suitable. It’s best (and easier) to
prevent than to treat.
 Combination therapy is much more effective
and associated with less riskthan repeat doses
of same agent.

53. PONV
 To date, more than 3000 articles on PONV
have been published,
 with more than 300 articles added yearly. Most
are reports of randomized controlled trials for
the prevention of PONV
 yet it is apparent that the elusive “holy grail”
 PONV prevention has yet to be found

54. Thank you….