Fisiol e anat ponv.PONV anatomy and physiology,risk of

Fisiologia ed anatomia del
PONV

Importance of the issue
• PONV is :
– A limiting factor in the early discharge of ambulatory surgical
patients
– The leading cause of unanticipated hospital admission
• PONV may:
– Increase recovery room time
– Expand nursing care
– Increase total health care costs
– Cause high level of patient discomfort---
pain,hematoma,wound dehiscence…
– Cause high level of patient dissatisfaction
– KO!!!

Macario A, Weinger M,Carney S, Kim A.Which
clinical anesthesia outcomes are important to
avoid?Anesth.Analg.1999;89:652-8.
20
18
16
14
12
10
8
6
4
2
0
rank valore relativo
vomito
gagging sul tubo
dolore
nausea
ricordo senza dolore
debolezza residua
brivido
mal di gola
sonnolenza
Dal +
indesiderabile
Al meno
indesiderabile
distribute $100 among the 10 outcomes
, proportionally more money being allocated
to the more undesirable outcomes.
The dollar allocations were used to
determine the relative value of each outcome.

Sintomi accusati dai pazienti a casa dopo
interventi eseguiti in regime di day surgery(da
Wu et al.,Anesthesiology 2002).
dolore
nausea
vomito
cefalea
sonnolenza
gir.di testa
fatica

Quali problemi preferirebbero evitare i pazienti
sottoposti a day surgery? (da Jenkins, K.; Grady, D.; Wong, J.;
Correa, R.; Armanious, S.; Chung, F.*Post-operative recovery: day surgery patients'
preferences
Br. J. Anaesth. 2001; 86:272-274)
30
25
20
15
10
5
0
dolore
tossire sul tubo et
vomito
nausea
disorientamento
mal di gola
brivido
sonnolenza
sete
Valori relativi !

Beauregard L, Pomp A, Choinière M.
Severity and impact of pain after day-surgery Can J
Anaesth 1998 / 45 / 304-11
100
90
80
70
60
50
40
30
20
10
0
%
dolore PONV gir.testa sonnolenza cefalea mal di gola raucedine fatica
I g.
II g
VII g

Methodological questions(from
Servizio di Anestesia e
Rianimazione Ospedale
di Faenza(RA)
Visserer et al…)
• definitions of PONV:
– nausea only,
– nausea and vomiting
– vomiting only.
• Diversity in methods of data collection
• Emetic symptoms can be quantified as:
– retrospective self-report
– established through explicit questioning
– observed on site by a third party.
– As a consequence of the effects of both suggestion and increased
detection, repeatedly questioning patients about PONV might result in a
higher percentage of patients reporting PONV and receiving antiemetic
therapy than would be the case in normal practice.

• So is PONV still a problem? It's been the most common problem in anesthesia for
decades; you would think that we would have a handle on it, right? And the problem is that
every time someone goes out and does a study and looks at "the big bad world," where
thousands and thousands of patients are being done, it still comes out to be 25% to 30%
after general anesthesia. That's the way it always is. No one believes me when I tell them
this; as a matter of fact, I didn't believe my practice was that bad either in Miami, Florida,
and I went to the PACU nurses and I said, "What's our incidence of PONV?" I don't know,
8%, 10% probably. And then when we studied it because we do a lot of actual clinical
studies, it turns out it's 30%. If you actually ask and you actually follow the patients for a
significant amount of time, you find out that no matter how good you think you're doing,
you're not actually doing as good as you think. So I want you to keep that in mind; just have
a little bit of an open mind about what the true incidence is. Most people don't think that
they're having this incidence and I'm going to show you why.
• You can get up to 80% with high-risk procedures using emetogenic anesthetics.
Laparoscopic gynecologic surgery: there was one paper published using a lot of narcotics
and desflurane that had an incidence above 80%. So if you really mix things up and get in
the worst of all worlds, you can almost guarantee your patient's going to get PONV.

• And we just talked how everybody's estimate
of PONV is less than the actual occurrence
and that's a lot because once the patient
leaves the recovery room, we don't really
think that much about the patient. Once we
send them out the door, whether it's to go
home or whether it is to go to the floor, we
don't always say, "Five hours after you left
me, did you have nausea and vomiting?"
You just want to know that they're doing okay

Oh,ma i dati sono vecchi di 13
anni…..

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

Risk and consequences of
vomiting
• Muscular contraction of the effort:
– Suture tension,stitches ,deiscence
• Regurgitation
• Aspiration pneumonia
– Electrolyre imbalance,dehydration
– Delay of oral intake
• Economic burden:
– Nurses time ,call,cleaning up
– Drugs for ponv
– Laundry
– Discharge delay
– Unplanned hospitalization..bed blocking….reduced surgical
throughput

PONV risk scoring systems
• Palazzo &Evans(BJA 1993):
– Logit postop sickness=-5.03+2.24(postop opioids)
+3.97(previous sickness history)+2.4(gender)
+0.78(history of motion sickness )-
3.2(gender*previous sickness history)
• Koivuranta(Anaesthesia 1997)
– Score=0.93(if female)+0.82(if previousPONV)+0.75(if
duration of surgery >60 min)+0.61(if non smoker)
+0.59(if history of motion sickness)

Independent predictors of
PONV Sinclair et al.Can PONV be predicted?Anesthesiology
• age A 10-yr increase in age was associa1te9d9 w9it;h9 a1 1:31%0 9de-c1re8ase in the likelihood of PONV.
• sex Men had one third the risk for PONV compared with women.
• smoking status Smokers had two thirds the risk for PONV compared with nonsmokers
• history of previous PONV, had a threefold increase in the likelihood PONV compared with patients
with no previous PONV.
• type of anesthesia: General anesthesia increased the likelihood of PONV 11 times compared with
other types of anesthesia.
• duration of anesthesia, direct association between the duration of anesthesia and the risk for
PONV. A 30-min increase in duration predicted a 59% increase in the incidence of PONV
• type of surgery :
– plastic surgery had a sevenfold increase in the risk for PONV.
– orthopedic shoulder surgery, ophthalmologic, or ENT procedures had a four- to sixfold
increase.
– orthopedic (nonshoulder) and gynecologic (non-D&C) procedures had a threefold
increase in the risk for PONV. Compared with the reference group, which
includes general surgery, gynecologic dilation and curettage (D&C), urologic
surgery, neurosurgery, and chronic pain blockENT
– dental surgery 14.3%, orthopedic 7.6%,plastic surgery 7.4%.Urologic,
gynecologic, neurologic, or general surgery had an incidence of PONV
corresponding to the overall average 4%
di Faenza(RA)
•

Logistic regression da:Sinclair et al.Can PONV be predicted?
di Faenza(RA)
Anesthesiology 1999;91:109-18
• P=1/1+e esponente
• con il segno neg. all’esponente la probabilità aumenta
perché e elevato ad esp negativo diminuisce sempre +
con il risultato che 1+e tende a 1 e dunque P=1/1,ossia
100%
• Con il segno positivo all’esponente e aumenta sempre + e
allora 1+e aumenta e dunque il denominatore
dell’equazione aumenta e dunque 1/un numero in
aumento fa scendere la probabilità perché viene 1/5,cioè
20%,1/10=10%,ecc…..

Formula di Sinclair
• P=1/1+e esponente
• Esponente=-5,97+(-0,14 *age)+(-1,03*sex)+
(-0,42*smoke)+(1,14*PONV history)+
(0,46*duration)+(2,36*GA)+(1,48*ENT)+
(1,77*ophtalm)+(1,90*plastic)+(1,20 Gynecol non DC)+(1,04 ort knee)
+(1,78*ortshoulder)+(0.94 ort other)
• Age = age in years/10;
• Sex = 1 if male and 0 if female;
• Smoke = 1 if smoker and 0 if nonsmoker;
• PONV History = 1 if previous PONV and 0 if no previous PONV;
• Duration = duration of surgery in 30-min increments;
• GA = 1 if general anesthesia and 0 if other type of anesthesia;
• ENT = 1 if ENT and 0 if other type of surgery;
• Ophthalm = 1 if ophthalmology and 0 if other type of surgery;
• Plastic = 1 if plastic surgery and 0 if other type of surgery;
• GynNonDC = 1 if gynecologic non D&C procedure and 0 if other type of surgery;
• OrtKnee = 1 if orthopedic procedure involving knee and 0 if other type of surgery;
• OrtShoulder = 1 if orthopedic procedure involving the shoulder and 0 if other type of surgery;
• OrtOther = 1 if orthopedic procedure involving neither knee nor shoulder and 0 if other type of
surgery.

Importance of the work by
di Faenza(RA)
Sinclair et al…
• Fitting the model to the data, we can obtain the
maximum likelihood estimate of the parameters
for each variable. Based on the maximum
likelihood estimates from the final models, it is
possible to calculate an expected risk of
occurrence of the specific adverse event for any
patient.
•

di Faenza(RA)
Examples
• The risk for patient 1, a 30-yr-old woman with a history of smoking and previous
PONV undergoing a 1-h shoulder (orthopedic) operation with general anesthesia is
35.2%.
•
• The risk for patient 2, a 40-yr-old nonsmoking man with no previous PONV
undergoing a 1-h knee arthroscopy (orthopedic) without general anesthesia is 0.4%.
•
• The risk for patient 3, a 70-yr-old smoking man with no previous PONV
undergoing a 1-h cataract surgery (ophthalmologic) without general anesthesia is
0.3%.
•
• The risk for patient 4, a 32-yr-old nonsmoking woman with previous PONV
undergoing a 30-min laparoscopy (gynecologic) with general anesthesia is 22.1%
•
• The risk for patient 5, a 22-yr-old woman with a history of smoking and previous
PONV undergoing a 90-min bilateral breast augmentation (plastic surgery) with
general anesthesia is 52%.

di Faenza(RA)
Risk Factors
• Non-anesthetic factors
• Anesthetic related
factors
• Postoperative factors

Risk factors da Samba 2007:1
• Patient specific
• Female gender
• Non smoking status
• Hx of ponv/motion sickness
di Faenza(RA)

• Anesthetic risk factors
–Use of intraop volatile anesth
–Use of intraop and postop opioids
–Use of intraop N2O
di Faenza(RA)

• Surgical risk factors
• Duration of surgery
– Each 30 min increase in duration of
surgery increases the risk by 60%,so that a
baseline risk of 10% increases to 16% after
30 min
• Type of surgery
– Laparoscopy;laparotomy;breast,strabismu
s,plastic,maxillofacial,gynecological,abdo
minal,neurologic ,opthalmologic,urologic
di Faenza(RA)

Non-anesthetic Factors
di Faenza(RA)
Risk Factors
• Age
• Gender
• Body habitus
• Hx motion sickness
• Hx PONV
• Anxiety
• Concomitant disease
• Operative procedure
• Duration of surgery

Anesthetic Related Factors
di Faenza(RA)
Risk Factors
• Preanesthetic
medication
• Gastric distension
• Gastric suctioning
• Anesthetic technique
• Anesthetic agents

Postoperative Factors
di Faenza(RA)
Risk Factors
• Pain
• Dizziness
• Ambulation
• Oral intake
• Opioids

Postoperative Nausea and Vomiting:
Anesthetic Related Factors
• Nitrous oxide
• Volatile
anesthetics
• NMB reversal
• Propofol
di Faenza(RA)

di Faenza(RA)
Risk Factors
Nitrous Oxide and PONV
Omission of Nitrous Oxide during Anesthesia Reduces
the Incidence of Postoperative Nausea and Vomiting. A
Meta-Analysis
Divatia et al. Anesthesiology 1996;85:1055-1062
Twenty-Four of Twenty-Seven Studies Show a Greater
Incidence of Emesis Associated with Nitrous Oxide than
with Alternative Anesthetics
Hartung. Anesth Analg 1996;83:114-116
Omitting Nitrous Oxide in General Anaesthesia:
Meta-Analysis of Intraoperative Awareness and
Postoperative Emesis in Randomized Controlled Trials
Tramer et al. BJA 1996;76:186-193

Omitting nitrous oxide from general anesthesia:
di Faenza(RA)
Risk Factors
Nitrous Oxide and PONV
• Decreases POV significantly only if the
baseline risk is high
• Does not affect nausea or complete control
of emesis
• Increases the incidence of intraoperative
awareness
Tramer et al. BJA 1996;76:186-193

Intravenous Fluid Therapy
Incidence of Postop Nausea
20
15
10
5
0
30 min 60 min DIS Day 1
di Faenza(RA)
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

P-6 Acupuncture Point
Stimulation
TAES Sham Placebo
PACU 25 17 28
45 min 36 51 32
90 min 27* 51 33
120 min 27 40 41
4 hr 26* 52 35
6 hr 22*† 47 43
9 hr 18*† 42 47
Servizio di Anestesia e Rianimazione Ospedale di
Faenza(RA)
Control of Nausea
Zarate E, et al. Anesth Analg 2001;92:629-35
* compared to sham
† compared to placebo

Supplemental Oxygen
• Greif R, Laciny S, Rapf B, et al. Supplemental
oxygen reduces the incidence of postoperative
nausea and vomiting. Anesthesiology
1999;91:1246-52.
• Goll V, Ozan A, Greif R, et al. Ondansetron is no
more effective than supplemental intraoperative
oxygen for prevention of postoperative nausea
and vomiting. Anesth Analg 2001;92:112-17.
di Faenza(RA)

Supplemental Oxygen
Faenza(RA)
30 % Oxygen 80% Oxygen P Value
Male/Female 57/62 41/71 0.110
0-6 hr PONV (%) 15.1 8 0.141
nausea (%) 15.1 8 0.077
vomiting (%) 1.7 0 0.169
6-24 hr PONV (%) 22.2 19.9 0.045
nausea (%) 17.6 8.9 0.066
vomiting (%) 5.9 1.8 0.108
0-24 hr PONV (%) 30.3 17 0.027
nausea (%) 27.7 16 0.034
vomiting (%) 5.9 1.8 0.108
Greif et al. Anesthesiology 1999;91:1246-1252

Supplemental Oxygen
Faenza(RA)
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

Pain and PONV
Effects % of Total Patients
Pain relieved, nausea relieved 68.5
Pain reduced, nausea relieved 11.5
Pain relieved, nausea persisted 9.5
Pain persisted, nausea persisted 10.5
di Faenza(RA)
Andersen et al. Can Anaesth Soc J 23:366-369, 1976

Transdermal scopolamine side
effects
• NO in a glaucoma patient
• No in a patient who has voiding problems
• It hasn't been approved in children
• don't cut the patch
• It has to be applied correctly
• can cause dry mouth.

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