Induction Principles and Technics - 5
Inhalational Induction and
If no IV is present, then inhalational induction is the gentle, pleasant best technic, allowing the anesthesiologist to practice her/his art as psychologist, physiologist, and pharmacologist.
Preoperative preparation is essential for optimum results. A simple "try on your mask" test may be used to help predict the likelihood of a smooth, calm inhalational induction. To do this test, the anesthesiologist or assistant
brings a mask of the appropriate size for the child to the preoperative waiting area or pre-surgical evaluation area. S/he states that this is the child's own mask, demonstrates how the mask is to be worn on her/himself,
then holds the mask out to the child. If the child promptly and happily takes the mask and places it correctly on her/his face, the likelihood of smooth inhalation induction is high. At the other extreme, if the child cries and
refuses to touch the mask, preoperative pharmacologic sedation and/or an alternate induction technic should be considered. If the child reluctantly tries on the mask only after considerable encouragement, unstressful inhalational
induction may still be accomplished if the child receives timely praise and positive reinforcement and it is pointed out that this wearing of the mask is ALL s/he will have to do in the operating room or induction area. In this case,
the anesthesiologist must make sure that wearing the mask is, in fact, all the patient is asked to do. In particular, no monitors other than the best one, the anesthesiologist, ought be used during the initiation of the induction; and the child
should not suddenly be asked to perform any tasks during induction such as "blow up the balloon" or "take some deep breaths." This later request is particularly undesirable in that the child may comply and hyperventilate enough to
then become apneic in a relatively light plane of anesthesia, so that any further stimulus (e.g., positive pressure ventilation, starting an IV) may result in laryngospasm. It is better and simpler to just trust the child to breath
as s/he has been doing all her/his life and calmly provide distracting reassurance with a soft touch and a soothing, story-telling tone of voice. If the child is reluctant to lie down, the induction may be performed with the child
sitting up and the anesthesiologist standing behind her/him, ready to support the child as s/he falls asleep. It is not necessary to abruptly, firmly plant the mask on the child's face. Rather, the mask may be slowly brought up from
below the child's chin and held at first near but not touching the face. The mask may be gradually brought to gently touch the face as the child becomes drowsy. As the patient is losing consciousness, the experienced pediatric anesthesiologist is the monitor.
Once the patient is asleep, her/his parent may be excused and escorted from the operating room, and a precordial stethoscope and pulse oximeter applied. In this manner even a somewhat frightened child can usually be guided through a smooth inhalational induction.
Patients Report Their Experience!
Although isoflurane inhalational inductions may be easily performed by slowly, gradually increasing the isoflurane concentration in 70% nitrous oxide in oxygen, more rapid inductions may be performed with the less pungent agents, halothane and sevoflurane. In fact, immediate 8% sevoflurane in 70% nitrous oxide in oxygen is well tolerated by ASA class I and II children who become completely quiet within about 30 seconds and spontaneously close their eyes within one minute.
If the infant or child comes to the operating room or induction room already very drowsy or asleep, then a "steal" induction may be performed. The operating room is kept quiet and the child is left completely undisturbed except that 70% nitrous oxide in oxygen is gently blown over her/his face. After a minute or two, a gradually increasing concentration of a major inhalational agent (usually halothane or sevoflurane) is added. The mask is slowly, gently brought into contact with the child's face as long as there is little or no response. At first, the anesthesiologist is the sole monitor. As the child makes a smooth transition from physiologic to anesthetic sleep, precordial stethoscope and pulse oximeter may be applied and the child moved to the operating table.
Patients Report Their Experience:12-year-old Katie describes her inhalational induction:
"The induction was performed with me lying down on a bed in the induction room. My mother and the anesthesiologist were there. The mask was put over my face and started the gas. It smelled weird. After three breaths, I was feeling sort of giggly. Then a second gas was started. It had a sweeter smell than the laughing gas. I was getting drowsy, and I heard the anestesiologist say to my mother, 'The gas is taking effect now.' I could feel my eyes closing, and my mother said, 'Sweet dreams, Katie,' and the next thing I knew, I was in the recovery room."
13-year-old Meredith describes her inhalational induction:
"I ended up going to sleep with a mask induction, and it wasn't so bad after all. They gave me a liquid sedative beforehand to make me very relaxed and a little sleepy, too. When they put the mask on me, I noticed the smell of the gas, but didn't really care because of the sedative. My eyelids got heavy, and I could feel myself drifting off, and then it was all over."