PONV Flashcards
What is the general incidence of N/V after surgery
30%
N&V can result in what complications
- aspiration
- wound disruption
- impaired healing
- increased surgical bleeding
Autonomic stimulation as a result of nausea and vomiting results in:
- Salivation
- Cutaneous vasoconstriction
- Tachycardia
- Mydriasis
- inhibition of gastric parietal cell secretion of acid, and altered gastric motility.
What are risk factors for PONV?
female, children, Hx PONV, motion sickness, non-smoker, opiate use, anxiety, obesity, long surgeries,
What detects motion stimuli from histamine or Ach receptors that can cause PONV?
The labyrinthine or vestibular apparatus and auricular branch of the tympanum of the ear
How can organs such as bladder, gallbladder, or uterus cause N/V?
Mechanoreceptors detect overdistention and disordered gastric motility
How does the vagus nerve reach the brain to stimulate N/V?
It signals histamine, cholinergic, or enkephalin receptors in the nucleus tracts solitaries or other centers in the area postrema and area subpostrema
What can stimulate the cortex and limbic system of the brain to cause N/V?
emotions, smells, sights, or thoughts
What is considered the vomiting center of the brain?
Medulla
What is located in the area postrema on the 4th ventricle of the brain and may identify absorbed toxins or disturbances such as hypotension or metabolic acid-base changes?
The Chemoreceptor trigger zone (CRTZ)
Where can H2 (histamine) receptors be found in the body?
Stomach (gastric)
CNS
heart
What does stimulation of H2 in the stomach result in?
an increased cAMP which activates the proton pump of gastric parietal cells which secrete H ion
What is the goal of given H2 blockers (Zantac, Pepcid)?
reduction of acidity of potentially aspirated gastric content
What is a potential side effect with the use of H2 blockers?
one concern is that H2 block causes unopposed H1 stimulation potentially resulting in bronchoconstriction
What can be used to treat the extrapyramidal side effects of Compazine?
Anticholinergics such as Benadryl