ANESTHESIA FACTS FOR NON-MEDICAL PEOPLE: WILL YOU BE NAUSEATED AFTER GENERAL ANESTHESIA?

One of the most common fears patients have before surgery is, “Will the anesthesia make me nauseated?

The answer is, “Possibly.”  The anesthesia medical literature contains thousands of published papers studying the science behind post-operative nausea and vomiting (PONV), and the best strategies to prevent it.

The four traits that have been found to best correlate with PONV are:

  1. female gender,
  2. a patient that does not smoke tobacco,
  3. a patient with a past history of PONV or motion sickness, and
  4. the use of postoperative intravenous narcotic pain relievers.

When 0, 1, 2, 3, or 4 of these factors are present, the risk for PONV is about 10%, 20%, 40%, 60%, or 80%, respectively.

If you are a woman smoker with a past history of nausea after anesthesia, and you are scheduled for a painful surgery that will require narcotic pain relievers, you have an 80% chance of having nausea after surgery.

If you are a man who smokes cigarettes, who has never been nauseated with past anesthetics, and your surgery is a trivial pain-free procedure on your finger, you have only a 10% chance of having nausea after surgery.

Overall, 20% to 30% of patients will experience nausea after surgery.  Nausea is the second most common complaint after surgery—pain is the most common complaint.

Anesthesia professionals typically give anti-nausea medications intravenously as prophylactic premedications to appropriate patients.  These medications may include combinations of ondansetron (Zofran), metoclopramide (Reglan), and/or dexamethasone (Decadron).

The onset time for PONV is usually in the first hour after awakening, during the time that the patient is observed in the Post Anesthesia Care Unit, or Recovery Room.  PONV can then be treated by additional rescue intravenous injections of potent anti-nausea medications such as promethazine (Phenergan).

Less commonly, patients who are discharged home the same day after surgery will have the onset of nausea either during the car ride home or when they begin their doses of oral narcotic pain relievers such as Vicodin.  Outpatient anti-nausea medications may be prescribed, including oral ondansetron (Zofran) or rectal suppositories of promethazine (Phenergan).

Of the four traits listed above that are associated with PONV, the anesthesiologist can do nothing to change the first three traits on any given patient.

However, the fourth trait can be manipulated.  The anesthesiologist and surgeon can make choices to minimize the need for postoperative intravenous narcotic pain relievers.  For certain procedures such as inguinal hernia repairs, bunionectomies, nasal surgeries, knee arthroscopies or breast biopsies, surgeons can inject local anesthetics into the surgical field to blunt post-operative pain.  For surgeries below the waist, anesthesiologists can utilize local anesthesia blocks such as spinal anesthesia or epidural anesthesia to blunt post-operative pain. For surgeries on a leg or an arm, anesthesiologists can utilize regional anesthetic nerve blocks to numb the leg or arm to blunt post-operative pain.

PONV can be such an negative experience that patients often rate it worse than postoperative pain.  Well-designed studies have shown that the amount of money that patients are “willing to pay out of pocket” for effective anti-nausea treatment of PONV is $56 per patient in the United States.  The prevention of PONV in high-risk patients significantly improves their ratings of well-being and satisfaction after surgery.

Discuss the prevention of PONV with your anesthesia professional prior to your surgery.  He or she will inform you of your risk, and the best approach to minimize your nausea after surgery.

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