Airway/Pulmonary Status

Respiratory mechanics alter dramatically from infancy to adulthood, resulting from increases in airway size, transformations in the rigidity of airway and chest structures, and major changes in neuromuscular status. A proportionally large head, a short neck, and a large tongue in relation to jaw size create more of a challenge for airway management. The glottis is very anterior, moving from the level of the second cervical vertebra to the level of the third to fourth vertebrae in the adult. The epiglottis is floppy and more curved, and the vocal cords are slanted anteriorly. The airway forms an inverse cone with the narrowest portion at the cricoid cartilage until 8 years of age; endotracheal tube size is therefore very important, since a tube that passes easily through the glottis may be too tight at the subglottic area, compromising the child’s airway in the immediate postoperative period because of swelling. The infant is an obligate nasal breather, and the chest wall of an infant is very compliant, leading to increased work of breathing with any type of airway compromise. Infants also have type 2 respiratory muscle fibers until age 2 years, which fatigue more easily than type 1 muscle fibers. Premature infants are at risk for postanesthetic apnea until 60 weeks after conception age. There is a depression in the CO₂ response curve in infants; compared to an adult, the respiratory rate does not increase as readily in response to a rising CO₂ level, although all ages undergo a CO₂ response depression related to inhalational agents and narcotics. One of the most important considerations is that children have a much smaller pulmonary functional residual capacity; a child becomes hypoxic more quickly if the airway is lost. Alveolar maturation is not complete until 8 years of age. Smaller airways have higher resistance; airway resistance decreases approximately 15 times from infancy to adulthood, again with a major change occurring around 8 years of age. It is important to note that smaller airways can become compromised with even a minor amount of swelling. Be aware that loose teeth are common in children aged 5 to 14 years; a dislodged tooth is a potential airway foreign-body risk.

Cardiovascular Status

The most dramatic changes in the cardiovascular system occur at birth with the transition from fetal circulation. Even in full-term infants, persistent transitional circulation may occur. Heart rate is the predominant determinant of cardiac output in infants and children; bradycardia drastically decreases cardiac output and requires swift intervention. There is a decreased cardiac compliance because of a lower proportion of muscle to connective tissue until age 1 to 2 years, making infants preload insensitive. Young children are predisposed to parasympathetic hypertonia (increased vagal tone), which can be induced by painful stimuli such as laryngoscopy, intubation, eye surgery, or abdominal retraction. Attention to blood loss in young patients is very important because the patient’s total blood volume is very small. Blood volume in neonates is 80 to 90 ml/kg; at 1 to 6 years it is 70 to 75 ml/kg; and at age 6 years to adult it is 65 to 70 ml/kg. At birth, 70% to 90% of the hemoglobin is fetal hemoglobin with a high affinity for oxygen. It is normal for hemoglobin levels to fall at about 2 to 3 months of age (physiologic anemia) to a hematocrit level of 29% and a hemoglobin level of 10 mg/dl as the infant’s body begins to produce its own blood cells. A cardiology evaluation is essential if a murmur is auscultated. A murmur can be from a patent foramen ovale, which normally closes at 3 to 12 months; a patent ductus arteriosus, which can be present for up to 2 months; a previously undetected cardiac anomaly; or an innocent flow murmur. The evaluation is critical because anesthetic agents cause vasodilation and potentiate cardiac dysrhythmias.

Temperature Regulation

Infants and young children are most at risk of hypothermia because of their increased body surface area/weight ratio and thin fat layer. Cold stress leads to increased oxygen consumption, resulting in hypoxia, respiratory depression, acidosis, hypoglycemia, and pulmonary vasoconstriction. Hypothermia alters drug metabolism, prolongs the action of neuromuscular blockers, and delays emergence from anesthesia. The child’s temperature must be monitored continuously throughout the intraoperative experience. An axillary temperature probe is acceptable for short procedures in healthy children; an esophageal or rectal temperature probe provides more accurate monitoring of the child’s temperature for longer procedures. Hyperthermia should also be avoided, because it leads to increased oxygen consumption and increased fluid losses.

It is vital to maintain normothermia in children, and the easiest way to do this is by exposing only the area on which surgery is being performed. Additional thermoregulatory interventions include altering the room temperature before the child enters the room, using a water-filled temperature-regulating blanket under the patient, or using a forced-air warming blanket over nonsurgical areas of the child. An overhead heater can be used during the anesthetic induction and patient preparation period immediately before prepping and draping. The anesthesia ventilation circuit can be heated and humidified, as can insufflated carbon dioxide during minimally invasive surgical procedures. For surgical procedures with large areas of exposure, warmed solutions should be available for use instead of room temperature solutions. Intravenous (IV) solutions can also be warmed before administration.

Metabolism

Infants have a higher basal metabolic rate than adults, and it is greatest at 18 months. Most importantly, children younger than age 2 years have immature liver function; pharmacologic response is altered, and there is slower hepatic clearance, decreased hepatic enzyme function, and decreased protein binding. Drug distribution is different in neonates and infants compared with older children and adults because of an increased percentage of total body weight and extracellular body fluid. Infants have an immature blood-brain barrier and decreased protein binding, which results in an increased sensitivity to sedatives, opioids, and hypnotics.

Fluid Management

Renal function at birth is immature, and the ability of the kidneys to concentrate urine is limited, so the infant is much more prone to dehydration. Complete maturation of renal function occurs at about 2 years. Compared to an adult, a child has a higher body water weight, a higher body surface area, and an increased metabolic rate, resulting in increased fluid requirements per kilogram of body weight. Despite these significant points, it is also important to remember that the body weight of the child, the length of time without fluids, and surgical losses are the primary factors in the calculations of the child’s hydration needs.

Planning and Preparation

Assessment data, combined with information about the planned surgical procedure, enable the surgical technologist to anticipate requirements for surgical positioning, instrumentation, equipment and supplies, medications, and activities necessary for the provision of safe, competent care for the pediatric patient.

The presence of a parent during much of the preoperative period, including during anesthesia induction in the OR and after anesthesia emergence in the PACU, can help decrease anxiety for both young children and their families and facilitates family-centered care (Evidence for Practice).

Infants, reliant on family to meet their basic needs, are difficult to pacify when NPO for surgery. The facility should provide rocking chairs, pacifiers, warm blankets, and simple distractions such as music or toys. Preoperative teaching should include telling the family to provide fluids for the infant until the deadline for NPO status. Unnecessary delays should be avoided at all costs. Parents may need reassurance and support during the period immediately before surgery.

The toddler or preschooler fears parental separation and abandonment. Toddlers fear, among other things, strangers, the dark, and machines. They attribute lifelike qualities to inanimate objects, believing that the objects, like them, have feelings. Thus a blood pressure cuff that squeezes the child’s arm may be perceived to be doing so because it is angry with the toddler. Toddlers may also believe that their body is held together by their skin; anything that violates the skin integrity is feared. For this reason, bandages are very important. Toddlers and preschoolers interact with the environment using their senses. To integrate this into the patient’s care, give the toddler the opportunity to touch and play with objects that he or she will encounter. An example is to give the child a small anesthesia mask to put on his or her teddy bear. Sensory information should be provided in a soft, gentle voice (i.e., what the toddler will see, feel, touch, and hear). A security object is extremely comforting. The OR should be quiet; background noise should be controlled. Instruments that are frightening should be kept from view. To allow quick induction of anesthesia the toddler should be transferred into the surgical suite when the room and staff are completely prepared.

The school-age child may still perceive hospitalization or surgery as a punishment but can evaluate painful intrusive actions in terms of logical function (e.g., getting an IV line hurts, but then I can get medicine in it to make me feel better). Feelings of inadequacy may be associated with something the child thinks he or she should be expected to do or know. Fear of body injury or mutilation, loss of control, and fear of the unknown characterize this developmental stage. These children benefit from simple, concrete explanations in familiar terms; a book or other teaching aid can be helpful. The concepts of time and unseen body functions can now be incorporated in the explanations. The child should be allowed to make choices when possible (e.g., letting the child decide in which hand to place the IV line or which flavor to add to the anesthetic mask).

Adolescents may fear altered body image, peer rejection, disability, and loss of control or status. The fear of death is more prevalent in this age-group than any other, and adolescents may find explanations of monitoring and safety measures reassuring. They need as much privacy as possible, and their attempts to be independent should be respected (e.g., walking into the OR instead of being wheeled in on a stretcher if the patient has not been sedated). The adolescent may not wish to show any fear; questions might not be asked while the parents are present. Information and explanations should be provided as reasonably and truthfully as possible. If appropriate, some choices should be allowed, such as wearing underwear to the OR. Patient care procedures that violate privacy, such as hair removal, skin preparation, or insertion of an indwelling urinary catheter, should be conducted after the patient is anesthetized.

Key points in providing perioperative care to pediatric patients include remaining alongside the child until the child is anesthetized, keeping the room quiet during induction, accepting a child’s need to express fear and fearful behaviors (e.g., crying), and using simple words without double meanings to explain care. Security objects should remain with the child until induction has been completed. A child’s behavior during induction is likely to be the same during emergence; thus all attempts should be made to provide calm, reassuring care. Parents should be alerted to delays in the surgery schedule; in some instances, the child may be allowed to have fluids if the surgery is delayed by several hours.

Remaining with the child during induction, positioning, and prepping the surgical site; creating and maintaining a sterile field; collecting, documenting, and disposing specimens; and administering medications are all part of helping to provide a safe environment for the pediatric surgical patient.

Central Venous Catheter Placement

The preferred site of placement is the external jugular vein. The internal jugular vein may be chosen if the external jugular vein has been used or is too small. From the cannulation site the catheter is tunneled under the skin about 5 to 10 cm. This is done to inhibit contamination of the bloodstream from frequent dressing changes. Subcutaneous ports are placed in a similar fashion. In cases where the internal or external vein sites are unavailable, the catheter may be placed into the external iliac vein by way of a cutdown in the greater saphenous vein. In these cases the catheter is tunneled into the abdominal wall.