After the child is completely anesthetized, a plastic tube is placed in the trachea or windpipe. This process is known as intubation and allows the anesthesiologist to control the size and rate of the breaths the patient receives.
Following intubation, a catheter is placed in one of the arteries (usually in a wrist or ankle) in order to allow continuous measurement of blood pressure and frequent blood sampling.
The blood samples are analyzed to determine the amounts of oxygen and carbon dioxide in the blood, concentration of blood sugar, and the adequacy of anticoagulation (a test called an ACT).
The anesthesiologist uses the results of the blood test to determine if changes are needed in the ventilator settings, if glucose needs to be added to the IV solution, or if additional blood thinning medication (heparin) is needed.
In many cases, a central venous catheter is placed. This is a special IV catheter that is placed into one of the large veins which drains directly into the heart. These catheters are helpful for administering potent medications safely and to monitor pressures around the heart.
Induction agents are the drugs used to get a child "off to sleep." An anesthetic sleep is not like a normal sleep. During normal sleep a child would awaken if stimulated. This does not happen during an anesthetic sleep if sufficient amounts of anesthetic are given. It is important for your child to understand this.
- Many children in the 6- to 12-year-old range are especially concerned about this and need to be reassured that they will be pain-free and totally unaware that they are having an operation. A six-hour operation may seem like only a few minutes to the child under a general anesthetic.
The method and drugs used during the induction of anesthesia depend on a variety of factors including the age of the child and his or her medical condition. The induction of anesthesia will be one of the topics your anesthesiologist will discuss with you the day before surgery.
Some children coming for surgery arrive at the hospital on the morning of surgery. The majority of children will not need to have an IV placed before they are asleep. These children can be induced using an "inhalational anesthetic" (gas), usually sevoflurane.
A sedated child is generally able to breathe off to sleep without becoming upset or anxious. All procedures that could cause pain (starting IVs, etc.) are performed after the child is under the anesthetic, so the child will not be aware that the procedures are happening.
Children with certain types of heart disease may or may not be able to tolerate an inhalational (gas) induction. Children who fall into this group include those with severe heart failure, significant pulmonary hypertension, and those with severe aortic stenosis.
If the anesthesiologist decides your child is not a good candidate for an inhalation induction, then one of two options may be used.
The child may have an IV placed and receive an intravenous induction drug (fentanyl, etomidate or ketamine), or the anesthetic may be administered as an intramuscular injection.
The drug most commonly used in this way is ketamine. Teenagers or young adults with heart defects that do not produce serious symptoms may receive the drug propofol as an induction agent.
During the operation, anesthesia will usually be maintained with a variety of anesthetic agents. Most children will receive intermittent doses of a strong narcotic (such as fentanyl) throughout the procedure. The dose given will depend on a variety of factors.
In children under 6 months of age, the anesthetic will primarily consist of high dose fentanyl. Fentanyl does however depress the drive to breathe. As a result, infants receiving a high dose fentanyl anesthetic will require a ventilator for at least 6 to 12 hours after surgery.
Since most of these patients will require breathing support because of their heart problems, the use of fentanyl in infants with complex heart defects is not a problem.
Many children will also be given an inhalation anesthetic such as sevoflurane or isoflurane which provide amnesia, unconsciousness, and analgesia.
Among children not receiving inhalation anesthetics, many will receive midazolam, which provides amnesia, in addition to a narcotic like fentanyl.
Each child who comes to the operating room for cardiac surgery has his or her own distinct cardiac defect and anesthetic issues.
The job of an anesthesiologist is to tailor an anesthetic using the various agents available that provides both comfort and safety for each child.
Parents, as well as children, should feel free to ask about the various medications they are to receive and the reasoning behind the use of those medications during their procedure.
