الفهرس 
Physiology of Nausea and VomitingOnly 14 pages are availabe for public view
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Abstract
The role of postoperative nausea and vomiting (PONV)
is often underestimated by anesthesiologists compared with
other perioperative complications. It seems to be of minor
importance. Rarely, it is lethal for the patient and almost never
becomes chronic but it is an unpleasant experience for the
patient.
Physiology of nausea and vomiting key structures and
pathways identified are:
The chemoreceptor trigger zone located in the area postrema
receiving inputs from blood-born drugs or hormones and
stimulated by them.
Vomiting center in the reticular formation, it coordinates the
visceral and somatic components of the vomiting reflex.
Risk factors of PONV
١) Patient-specific
Female gender, non smoking, history of PONV, motion
sickness, migrane, age, increases in children), obesity.
٢) Anesthesia-related independent predictors: unexperienced
anesthetists Anesthetic agents like opioids, nitrous oxide, some
intravenous agents like ketamine and volatile anesthetic
agents, regional anesthesia.
٣) Surgery-related factors
Type and duration of surgery.
Management of postoperative nausea and vomiting.
Guideline ١: Identify Patients’ Risk for PONV
Guideline ٢: Reduce Baseline Risk Factors for PONV
Guideline ٣: Administer PONV Prophylaxis Using One to
Two Interventions in Adults at Moderate Risk for PONV
Guideline ٤: Administer Prophylactic Therapy with
Combination (>٢) Interventions/Multimodal Therapy in
Patients at High Risk for PONV.
Guideline ٥: Administer Prophylactic Antiemetic Therapy to
Children at Increased Risk for POV; as in Adults, Use of
Combination Therapy Is Most Effective
Guideline ٦: Provide Antiemetic Treatment to Patients with
PONV Who Did Not Receive Prophylaxis or in Whom
Prophylaxis Failed.
The study included ١٢٠ patients. Their ages vary from ٢٠
to ٥٠ years old. ASA physical status I and II; with or without
history of POV or motion sickness undergone (laparoscopic
surgery. The patients are allocated randomly into six groups
according to the antiemetic drug combination given. Each
group consists of ٢٠ patients. group (DM): received ٨ mg dexamethasone and
٠٫١٥ mg/kg metoclopramide.
group (MO): received ٠٫١ mg/kg ondansetron and
٠٫١٥ mg/kg metoclopramide.
group (MG): received ٠٫١٥ mg/kg metoclopramide and
٠٫٠١ mg/kg IV granisetron.
group (DO): received ٨ mg dexamethasone and
٠٫١ mg/kg ondansetron.
group (DG): received ٨ mg dexamethasone and ٠٫٠١ mg/kg
granisteron.
group (P): received normal saline.
Exclusion criteria included:
١- Patients with ASA > II.
٢- Cardiac disease.
٣- Neurological disease.
٤- Gastrointestinal disease.
٥- Mental retardation.
٦- Psychiatric illness.
٧- Severe renal or hepatic disease.
٨- Pregnancy, menstruating females, breast feeding,
antiemetic or glucocorticoids, within ٢٤ hours of
surgery.
٩- Obesity
١٠- Allergy of used drugs.١١- Patients with contraindications for non steroidal antiinflammatory
drugs.
Assessment was done over ٢٤ hours after surgery as follows:
- Onset, severity of nausea.
- Frequency of attacks of vomiting.
- Need for rescue drugs.
- Incidence of side effects.
- Duration of PACU and ward stay.
Results obtained from the study suggested that the use of
combination of dexamethasone and selective serotomin receptor
antagonist was more effective than other combinations of either
٥-(HT٣) antagonists or dexamethasone with metoclopramide in
increasing the frequency of achieving complete control of
PONV including incidence, severity, need for rescue drugs and
shorter stay in PACU and ward.
Groups containing dexamethasone were more effective in
controlling late PONV, groups containing ٥-(HT٣) antagonists
were more effective in controlling early PONV.
The most common side effect was severe headache and it
was equal among all groups.