What do heart disease, diabetes, heartburn and high or low) blood pressure have in common? These are among the many conditions that can affect your response to anesthesia during surgery.

Each year, about 21 million Americans who undergo elective or emergency surgeries receive general anesthesia (a method of preventing pain by rendering a patient temporarily unconscious with drugs that are inhaled through a mask or given intravenously).

Possible complications…

  • Anesthesia awareness. According to research published in The New England Journal of Medicine, one or two in every 1,000 people who undergo general anesthesia "wake up to some degree during the operation.

This so-called "awareness" may allow patients to hear conversations in the operating room while they remain immobilized and unable to speak. In rare cases-about 30,000 surgeries in the US each year-patients also feel pain while they are unable to move or speak.

To avoid this problem, a patient's heart rate, blood pressure, breathing and other vital signs are closely monitored during general anesthesia. About 60% of operating rooms in the US also have bispectral index systems. These monitors record certain types of brain activity that can signal anesthesia awareness.

Among those at greatest risk: People who have low blood pressure. Because most anesthesia lowers blood pressure, people who have low blood pressure (chronic or acute, such as that due to injury-related blood loss) usually are given less anesthetic.

Also at risk: Heavy drinkers, who tend to metabolize anesthesia more quickly than people who do not drink heavily.

Self-defense: Tell your anesthesiologist if you have low blood pressure, and be completely honest about the amount of alcohol you drink.

  • Coma, neurological damage or death. These devastating complications occur in about one in every 250,000 surgeries in which general anesthesia is used each year in the US. The most common cause is failure of the medical team to "ventilate"-that is, provide a means for the patient to breathe

Among those at greatest risk: People who are obese-being overweight can cause obstruction of the airway, including the throat and larynx...those who have had prior surgery or radiation of the neck, mouth or airway-surgery or radiation to these areas can stiffen the tissues in the neck and mouth, making it more difficult to ventilate the patient...anyone with sleep apnca (temporary cessation of breathing during sleep)...or a history of difficulty when being intubated (insertion of a tube to keep the airway open) during past surgeries.

Self-defense: Tell your anesthesiologist if any of these risk factors apply to you. Even if you've never been diagnosed with sleep apnea, let him/her know if you snore at night or feel unusually tired during the day. These can be signs of sleep apnea, which obstructs the airway.

  • Pneumonia. Thousands of Americans develop anesthesia-related pneumonia each year. One of the most common causes is the backup (reflux) of stomach acid, which can be inhaled (aspirated) into the lungs while a patient is under anesthesia, leading to pneumonia.

Among those at greatest risk: People who have chronic heartburn (known as gastroesophageal reflux disease, or GERD) or a hiatal bernia (in which the stomach passes partly or completely into the chest cavity)—both conditions make patients prone to aspiration...and those who are obese, have diabetes or diseases of the nervous system, such as Parkinson's disease. Obesity, diabetes and nervous system disorders increase risk for aspiration because they can delay emptying of stomach contents.

Self-defense: Your anesthesiologist may not ask about heartburn or hiatal hernia, but it's important to tell him if you are affected by these conditions. If you do have GERD, drugs that reduce stomach acid, such as lansoprazole (Prevac id) or ranitidine (Zantac), may be prescribed.

Important: Follow your hospital's guidelines on food and liquid intake before surgery.

  • Heart attack or stroke. Each year, about one in 10,000 patients suffer heart attack or stroke while under anesthesia.

Among those at greatest risk: People with high blood pressure (140/90 or above) and/or heart disease. A history of high blood pressure can increase a patient's risk for stroke because of accompanying blood vessel changes, such as stiffening of the arteries. Heart disease often causes a thickening of the arteries to the heart that can lead to cardiovascular complications during anesthesia, resulting in heart attack.

Self-defense: Inform your anesthesiologist if you have high blood pressure or heart disease.

Getting The Best Care

Most surgical patients do not meet the anesthesiologist until moments before surgery. Ask your surgeon beforehand who will be administering the anesthetic and whether you can meet with him a day or two before the surgery so that he has more time to review your medical history and address any of your concerns.

Tell your anesthesiologist if…

  • You take any medications or supplements. Blood pressure, diabetes and blood-thinning drugs are among those that may need to be discontinued prior to surgery. Speak to your surgeon for specific instructions. Herbal remedies, including St. John's wort and garlic, may need to be discontinued before the operation because they may interact with the anesthetic.
  • Anyone in your family has ever had a bad reaction to general anesthesia, such as delayed awakening. In some cases, bad reactions to anesthesia may be genetic.

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