The Postanesthesia Care Unit
General Management
All children should be transported to the postanesthesia care unit (PACU) in the lateral decubitus position with the head extended so as to provide an unobstructed airway; all children—other than absolutely healthy children having minor surgery—should receive oxygen and be monitored with Sp O 2 during transport to PACU. The anesthesiologist walks at the head of the bed facing forward so as to be in the optimal position to observe the child and then monitors the child continuously. During transfer to the PACU, there is a danger of respiratory obstruction, so be alert to this possibility. If the airway is in doubt, do not leave the operating room (OR). If the airway becomes precarious while on route to the PACU, apply digital pressure to the condyle of the mandible behind the pinna to open the upper airway. There is evidence that decreases in Sp O 2 during transport are most likely due to airway obstruction. Children with a history of upper respiratory tract infections (URTI) are particularly at risk.
In the PACU, the anesthesiologist:
- 1.
Transfers the child to the care of the PACU nurses (see later discussion); summarizes the child’s underlying medical and surgical conditions, the operative procedure and any associated issues (e.g., bleeding, vascular compromise); provides the timing and doses of antibiotics and analgesics, intravenous fluid therapy, and blood loss and replacement; and describes the anesthesia technique including any complications and their management.
- 2.
Completes the anesthesia record with the initial vital signs in PACU.
- 3.
Writes postoperative (PACU) orders, including pain and antiemesis orders, intravenous fluids, and respiratory therapy.
- 4.
Confirms the child’s vital signs on arrival are recorded by the receiving nurse.
- 5.
Remains with the child until it is safe to transfer the care to the PACU nurses.
In the PACU, every child receives humidified oxygen via face mask or nasal prongs as tolerated. The anesthesiologist should not transfer the care of a child to the PACU nursing staff if there is any doubt about the airway, that ventilation is inadequate, and requires an oropharyngeal airway or tracheal tube. A child who still requires an oropharyngeal airway may still need an anesthesiologist.
Remember that small infants (younger than 3 months of age) may not rapidly convert to mouth-breathing if the nasal passages are blocked (i.e., after cleft lip or palate repair). If such obstruction occurs, insert an oropharyngeal or nasopharyngeal airway for patency until the child is fully awake. Also, an orogastric tube may be inserted before emergence to decompress the stomach (and may also serve to open the oral airway).
The progress of recovery should be documented with a postanesthesia scoring system along with regular recording of the vital signs. All children should receive oxygen initially until they awaken and can maintain an adequate Sp O 2 in room air. Sp O 2 should be continuously monitored until the child is fully awake and ready for discharge.
As soon as the child begins to awaken, with stable vital signs and good pain control, the parents should be brought to the bedside. This decreases the child’s anxiety in the PACU, reduces crying, and reduces the need for sedation. It also clarifies whether the child is crying because of pain or because of separation from parents.
After ketamine anesthesia, recovery should take place in a quiet dimly lit area with minimal tactile and auditory stimulation. If, despite these precautions, delirium and/or hallucinations develop, midazolam 0.05 to 0.1 mg/kg IV or diazepam (0.1 to 0.2 mg/kg IV) may be administered.
Complications in the Postanesthesia Care Unit
Laryngospasm
Laryngospasm occurs most commonly during emergence from anesthesia. During anesthesia, it may be treated as outlined below and possibly by deepening the level of anesthesia. During extubation and recovery, it is more likely to occur in children with blood or secretions in the pharynx or in those with a history of URTI (see Chapter 4 ). It should be managed by bag-mask ventilation with oxygen, maintaining positive pressure, and subluxation of the TMJ. Be prepared to administer a short-acting muscle relaxant; reintubate the trachea if necessary and do not delay reintubation if desaturation progresses. Often a very low dose of succinylcholine (0.2 mg/kg) will relieve the laryngospasm. Noncardiogenic pulmonary edema may follow immediately upon relief of severe laryngospasm. If it occurs, treat with continued positive pressure ventilation, furosemide, fluid restriction, and supplemental oxygen as indicated.
Postoperative Stridor
Postoperative stridor caused by subglottic edema may occur especially after endoscopy, children with a history of croup, those who were intubated as neonates, or after the unwise use of too large an endotracheal tube. Stridor is also more common in children with Down syndrome and after surgery during which head movement occurred. Stridor usually appears within 30 to 60 minutes after extubation. The use of humidified oxygen and intravenous dexamethasone may reduce subglottic edema. If stridor persists, administer racemic epinephrine by spontaneous respirations or preferably intermittent positive-pressure breathing for 15 minutes; this is usually efficacious. Very rarely, it may be necessary to reintubate the airway in the PACU for persistent severe stridor. In such cases a smaller-diameter tube that is accompanied by an audible leak is preferred. If racemic epinephrine is used, then the child should be observed for an extended period of time for possible rebound edema.
Emergence Agitation
Agitation occurs most commonly but not exclusively in children 2 to 6 years of age after sevoflurane anesthesia, with a reported incidence up to 80%. Agitation has also been reported after desflurane, halothane, and isoflurane. It is characterized by the presence of restless, thrashing, and inconsolable behaviors; disorientation; failure to establish eye contact; and a lack of purposeful movement and awareness of their surroundings. The agitation is usually transient, dissipating spontaneously within 10 to 20 minutes, without sequelae. The incidence may be attenuated by pretreatment with propofol, fentanyl, dexmedetomidine, clonidine, or NSAIDs (ketorolac). Difficulty differentiating emergence agitation from postoperative pain has been addressed in part, with the introduction of a validated scale to measure agitation in children. Treatment in the PACU may require small doses of fentanyl.
Suggested Reading
Shivering and Rigidity
Shivering and rigidity may occur during recovery from anesthesia, sometimes associated with hypothermia and other times, in normothermic children. As this may increase the metabolic rate and oxygen requirement, it should be treated. If halothane is used for anesthesia, shivering may become so severe that it compromises the surgical results (e.g., in a child with a recently reduced fracture). Intravenous meperidine (Demerol) (0.25 mg/kg IV) or dexmedetomidine (0.5 μg/kg IV slowly) may eliminate the shivering.
Suggested Reading
Nausea and Vomiting
Postoperative nausea and vomiting may be troublesome in the recovery period; it is a leading cause of delayed discharge from the PACU or, more rarely, of unplanned admission of the day surgery patient. The incidence of PONV can be significantly reduced by some general measures:
- 1.
Avoid the indiscriminate use of opioids; a single dose dramatically increases PONV. Use alternative analgesic drugs (e.g., nonsteroidal antiinflammatory drugs [NSAIDs]) or regional analgesia whenever possible. However, pain itself may cause PONV—so ensure analgesia.
- 2.
Do not “push” oral fluids postoperatively; wait until the child asks for them or is thirsty.
- 3.
Do not rush to mobilize the child, especially after eye surgery.
When nausea and vomiting can be anticipated (e.g., eye surgery, tonsillectomy), the incidence can be reduced by the choice of the anesthetic regimen (e.g., propofol), by avoiding nitrous oxide (in emetogenic surgery), by administering large volumes of intravenous fluids (20 to 30 ml/kg) and by prophylactic multimodal antiemetic therapy (dexamethasone and a serotonin-receptor antagonist, such as ondansetron). In children with unexpected nausea and vomiting, rescue medication with an antiemetic drug is necessary ( Table 7-1 ).
| Dexamethasone | 100–150 μg/kg (Maximum 8 mg) |
| Ondansetron | 50–100 μg/kg (Maximum 4 mg) |
| Granisetron | 40 μg/kg (Maximum 0.6 mg) |
| Dimenhydrinate | 0.5 mg/kg (Maximum 25 mg) |
| Droperidol | 10–15 μg/kg (Maximum 1.25 mg) |
Dimenhydrinate and metoclopramide are both moderately effective antiemetics and cause little sedation. Droperidol in doses adequate to combat nausea and vomiting may cause sedation, with delayed recovery and discharge. Ondansetron, dolasetron, and granisetron are probably the most effective agents for PONV. (NB. Dolasetron has been associated with rare fatal arrhythmias in children.) Dexamethasone is very effective for PONV, particularly in children undergoing tonsillectomy and adenoidectomy and strabismus surgery. The combination of ondansetron (0.05 to 0.1 mg/kg) and dexamethasone (0.0625 to 0.15 mg/kg) is currently the optimal PONV prophylactic regimen.
Suggested Reading
Duration of Stay in the Postanesthesia Care Unit
Children remain in the PACU until they are fully awake and have recovered from the effects of anesthesia. As a general rule, a minimum stay of 30 minutes or two sets of vital signs is required. Infants weighing less than 5 kg are usually kept in the PACU for a more prolonged period or transferred to a monitored bed. Be alert for possible postoperative complications (e.g., stridor after surgery of or near the airway or after endoscopy; bleeding after a kidney or liver biopsy, tonsillectomy), and specify a longer stay in the PACU for such children.
Children who remain more than 1 hour in PACU must have deep-breathing and coughing exercises and be turned hourly. Each child should be signed out of the PACU by an anesthesiologist except for the most simple of cases (e.g., myringotomy). If the discharge order from the PACU is delegated to the nurse, specific written clinical criteria should be documented. If an anesthetic complication occurs, the child must be reevaluated by the anesthesia team before discharge from PACU.
MANAGEMENT OF PAIN
The ability of infants and children to feel pain was misunderstood in the past, and this led to its undertreatment. It is now recognized that the biochemical and nervous components of the pain perception pathways are completely formed during fetal life and that even the preterm infant can feel pain. Furthermore, the adverse effects of unmodified pain have been documented even in very young infants. Studies suggest that inadequate treatment of pain in infants may lead to increased sensitivity to pain later in life.
There are many reasons why pain in children was undertreated in the past and why even today it is inadequately treated:
- 1.
Infants cannot tell us when they feel pain, and it is sometimes difficult to determine whether they are crying because they are in pain or for another reason.
- 2.
The older child’s response to pain differs from that of the adult; often these children are quiet and withdrawn, failing to announce their discomfort.
- 3.
In the days when intramuscular injection of an opioid was the standard therapy for postoperative pain, children often feared the injection more than the pain and preferred to suffer in silence. This tended to perpetuate the myth that children do not feel pain as much as adults.
- 4.
Physicians have been uncertain of the safety of the analgesic drugs given to infants. It was stated that infants are “exquisitely sensitive” to the respiratory depressant effects of morphine; this led to an ultraconservative approach in prescribing opioids.
- 5.
Many physicians, and especially those junior staff to whom the responsibility for pain management was customarily delegated, were unsure of the correct dosage of analgesics for infants and children.
- 6.
Nurses have tended to underestimate pain in children; many healthcare providers have overestimated the danger of the child’s becoming addicted to opioids.
- 7.
If an opioid is administered, then the child must be observed for an extended period to assure that there is no respiratory compromise.
More recently, a much greater understanding of childhood pain has been acquired. We know that all children can experience pain, we are better equipped to assess the severity of the pain, and we have better means to control pain. Postoperative pain management should be planned when the preoperative evaluation is performed, and it should be discussed with the child and parents.
For outpatients it is most important that the parents are well instructed on the management of pain when the child arrives home:
- 1.
Analgesic drugs must be administered before pain becomes significant and repeated regularly by schedule rather than waiting for pain to be a problem.
- 2.
The “analgesic gap” as regional analgesia wears off must be anticipated (most often manifest by the child becoming irritable) and suitable analgesics administered in advance.
- 3.
Parents should be instructed to look for signs of pain, to use assessment tools (e.g., visual analog scales [VAS]) and to administer effective analgesics appropriately. A standard VAS may be sent home with the child for the parent’s use.
Assessment of Pain
It is essential for optimal pain management to establish regular, objective pain level assessments recorded on the medical record. For infants, the level of pain is assessed by physiologic or behavioral indices. Indices of pain include tachycardia, tachypnea, increased blood pressure, sweating, facial expressions, posture, and crying. Of the behavioral indices, facial expression may be most reliable, but cry characteristics and body movement (especially flexion of the limbs) are also useful. The opinion of the parent and of the child’s nurse in interpretation of these behavioral signs is very useful. These indices are incorporated into a numeric scale that can be scored and recorded ( Table 7-2 ).
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