Pediatric Anesthetic Techniques: Emergence & Recovery

Emergence & Recovery

Pediatric patients are particularly vulnerable to two postanesthetic complications: laryngospasm and postintubation croup. As with adult patients, postoperative pain requires close, careful attention. Pediatric anesthesia practice varies widely, particu-larly in regard to extubation following a general anesthetic. In some pediatric hospitals, all children who will be extubated after a general anesthetic arrive in the postanesthesia care unit (PACU) with the tube still in place. They are subsequently extu-bated by the PACU nurse when defined criteria are reached. In other centers, nearly all children are extubated in the operating room before arriving in the PACU. High quality and safety are reported at centers following either protocol.

A. Laryngospasm

Laryngospasm is a forceful, involuntary spasm of the laryngeal musculature caused by stimulation of the superior laryngeal nerve . It may occur at induction, emergence, or any time in between without an endotracheal tube. Presumably it can also occur when a tube is in place, but its occurrence will not be recognized. Laryngospasm is more common in young pediatric patients (almost 1 in 50 anesthetics) than in adults, and is most common in infants 1–3 months old. Laryngospasm at the end of a procedure can usually beavoided by extubating the patient either while awake (opening the eyes) or while deeply anesthetized (spontaneously breathing but not swallowing or coughing); both techniques have advocates and despite strong opinions, evidence is lacking as to which is the better approach. Extubation during the interval between these extremes, however, is gener-ally recognized as more hazardous. Recent URI or exposure to secondhand tobacco smoke predisposes children to laryngospasm on emergence. Treatment of laryngospasm includes gentle positive-pressure ventilation, forward jaw thrust, intravenous lido-caine (1–1.5 mg/kg), or paralysis with intravenous succinylcholine (0.5–1 mg/kg), or rocuronium (0.4 mg/kg) and controlled ventilation. Intra-muscular succinylcholine (4–6 mg/kg) remains an acceptable alternative in patients without intrave-nous access and in whom conservative measures have failed. Laryngospasm is usually an immediate postoperative event but may occur in the recovery room as the patient wakes up and chokes on pharyn-geal secretions. For this reason, recovering pediatric patients should be positioned in the lateral position so that oral secretions pool and drain away from the vocal cords. When the child begins to regain con-sciousness, having the parents at the bedside may reduce his or her anxiety.

B. Postintubation Croup

Croup is due to glottic or tracheal edema. Because the narrowest part of the pediatric airway is the cricoid cartilage, this is the most susceptible area. Croup is less common with endotracheal tubes that are small enough to allow a slight gas leak at 10–25 cm H ₂O. Postintubation croup is associated with early child-hood (age 1–4 years), repeated intubation attempts, overly large endotracheal tubes, prolonged surgery, head and neck procedures, and excessive movement of the tube (eg, coughing with the tube in place, mov-ing the patient’s head). Intravenous dexamethasone (0.25–0.5 mg/kg) may prevent formation of edema, and inhalation of nebulized racemic epinephrine (0.25–0.5 mL of a 2.25% solution in 2.5 mL nor-mal saline) is an often effective treatment. Although postintubation croup is a complication that occurs later than laryngospasm, it will almost always appear within 3 h after extubation.

C. Postoperative Pain Management

Pain in pediatric patients has received considerable attention in recent years, and over that time the use of regional anesthetic and analgesic techniques (as described above) has greatly increased. Commonly used parenteral opioids include fentanyl (1–2 mcg/ kg), morphine (0.05–0.1 mg/kg), hydromorphone (15 mcg/kg), and meperidine (0.5 mg/kg). A multi-modal technique incorporating ketorolac (0.5–0.75 mg/kg) will reduce opioid requirements. Oral, rec-tal, or intravenous acetaminophen may also be a helpful substitute for ketorolac.

Patient-controlled analgesia  can also be successfully used in patients as young as 6–7 years old, depending on their maturity and on preoperative preparation. Commonly used opi-oids include morphine and hydromorphone. With a 10-min lockout interval, the recommended interval dose is either morphine, 20 mcg/kg, or hydromor-phone, 5 mcg/kg. As with adults, continuous infu-sions increase the risk of respiratory depression; typical continuous infusion doses are morphine, 0–12 mcg/kg/h, or hydromorphone, 0–3 mcg/kg/h. The subcutaneous route may be used with morphine. Nurse-controlled and parent-controlled analgesia remain controversial but widely used techniques for pain control in children.

As with adults, epidural infusions for postopera-tive analgesia often consist of a local anesthetic com-bined with an opioid. Bupivacaine, 0.1–0.125%, or ropivacaine, 0.1–0.2%, are often combined with fen-tanyl, 2–2.5 mcg/mL (or equivalent concentrations of morphine or hydromorphone). Recommended infusion rates depend on the size of the patient, the final drug concentration, and the location of the epi-dural catheter, and range from 0.1 to 0.4 mL/kg/h. Local anesthetic infusions can also be used with continuous nerve block techniques, but this is less common than in adults.