RECOVERY FROM ANESTHESIA IS a continuum from the discontinuation of anesthetic agents to early recovery of consciousness, protection of airway reflexes, and cardiorespiratory stability through complete resumption of normal activities, which can take up to several days or longer. Early recovery involves the short-term reversal of the physiologic and behavioral alterations created by anesthesia and surgery and has the possibility for a number of potentially catastrophic problems. A child’s response to distress during this period is dependent on his or her cognitive and emotional development with significant individual variation. This chapter will focus on the process of recovery from anesthesia, procedural aspects of postanesthesia care, and postanesthesia care problems.

Modern general anesthetic agents allow for rapid emergence and awakening within several minutes of discontinuation. Current techniques often use a combination of various potent inhalational and intravenous agents as well as neuromuscular blockade and regional techniques. The variable rate of recovery from multiple categories of agents is well recognized but not well characterized. Recovery from inhalational anesthetics is a function of the agent, concentration, duration of use, blood and lipid solubility, and degree of metabolism and alveolar ventilation rate. Patients will usually begin to respond to verbal or other stimuli at approximately 0.5 MAC for inhalational anesthetics, a concentration referred to as “MAC awake.” Recovery from intravenous anesthetics depends on the agent, dose, timing of administration, lipid solubility, and drug metabolism. If neuromuscular blocking agents are used, a peripheral nerve stimulator should be used to monitor the neuromuscular blockade; the effectiveness of reversal agents should be monitored to minimize residual neuromuscular blockade. Tracheal extubation and respiratory support should be continued until neuromuscular blocking agents have been adequately antagonized.

PACU POLICES AND PROCEDURES

With a trend toward more outpatient surgeries and more pediatric imaging studies requiring anesthesia, the number of children in the United States undergoing outpatient anesthesia have surpassed the number of inpatient cases. In 2006, an estimated 2.3 million children under 15 years of age underwent ambulatory anesthesia—a 300% increase between 1996 and 2006 (1,2). As this trend continues, it is important to ensure the appropriate environment for safely monitoring, treating, and discharging these patients.

ORGANIZATION OF THE PACU

A PACU should provide access to close monitoring, emergency equipment, and highly trained staff who can help the patient transition from the physiologic perturbations of anesthesia and surgery to discharge home or an inpatient setting. With these considerations in mind, the PACU should be in close proximity to the OR to decrease transport time and have immediate access to anesthesiologists, nurses, and surgeons. Additionally, vital equipment including laboratory facilities and resuscitation equipment should be nearby, available to handle all issues that may arise during normal emergence from anesthesia as well as emergencies (Table 9.1) (1–4).

The size and number of bed spaces depend on the types of cases being performed and the number of ORs. To maximize patient flow, at least 1.5 to 2 beds per operating area or greater are required. The facility should have an open architecture to maximize the monitoring and safety of patients, but needs to have curtains or a more private area for “phase 2” recovery. Phase 2 recovery, defined as the care that follows the resumption of consciousness, stabilization of airway, hemodynamics, and pain control, allows patients to complete their recovery prior to discharge home. In some circumstances, the patients can go immediately to phase 2 recovery, called “fast-tracking.” Highly skilled and experienced PACU nursing staff provides the primary care. Initial care can often require a 1:1 or 2:1 staffing ratio for high-acuity patients and often 1:2 or greater after initial recovery. However, a large number of patients require physician intervention to manage pain, nausea/vomiting, delirium, and other cardiopulmonary events. Therefore, access to an anesthesiologist to help coordinate more complex patient care and manage emergencies is essential to providing safe and efficient care. The PACU staff should have physician supervision with a clear plan for identifying the anesthesiologist responsible for care of the patients (1–4).

TABLE 9.1  Pediatric PACU—physical and equipment requirements

ICU, intensive care unit.

TRANSPORT TO THE PACU

Patients transported to the PACU should be stable from both a respiratory and cardiovascular standpoint. Assuring the patient has an adequate airway with appropriate air exchange and oxygenation is a prerequisite prior to and during transport from the OR to the PACU. In children, whose respiratory status can rapidly deteriorate, an anesthesiologist needs to continuously monitor the patient during this transfer. Most anesthesiologists choose to transport pediatric patients with supplemental oxygen due to a high incidence of desaturation on arrival to the PACU (see subsequent text). If the patient has an endotracheal tube, oral, or nasal airway, the patency and position of the artificial airway needs close monitoring. All patients should be observed closely with the side rails of the bed or stretcher elevated to prevent injury to the patient or caretakers if the patient becomes agitated. The unconscious patient is often transported in the lateral position; this maintains airway patency and allows vomit or secretions to drain out of the pharynx instead of onto the vocal cords, which may precipitate laryngospasm. Additional monitoring such as pulse oximetry, invasive or noninvasive blood pressure, and electrocardiogram (ECG) should be used depending on the patient’s status. All intravenous lines, infusions, drains, and Foley catheter need to be secured carefully. High-acuity patients should be transported with medications and equipment necessary to maintain respiratory and cardiovascular stability, including equipment for bag-mask ventilation, laryngoscope, endotracheal tubes, anesthetic agents’ volume expanders, and vasopressors (4).

PACU ADMISSION

Upon arrival to the PACU, the anesthesiologist must assure a patent airway and adequate gas exchange, assist in placing monitors on the patient, and record the initial heart rate, respiratory rate, oxygen saturation, blood pressure, and temperature on the anesthesia record. When the patient has been stabilized, including reasonable pain control, report should be given to the PACU nurse. The report, or “hand-off,” should include the (1) The procedure performed, (2) medical and surgical history, (3) medications, (4) allergies, (5) anesthetic technique and the use and reversal of neuromuscular blocking agents, (6) fluid management, (7) blood loss, and (8) any special issues such as complications or difficulties with the anesthetic or surgical procedure. Details of airway management (endotracheal tube, laryngeal mask airway [LMA], or mask, and whether the patient was extubated deep or awake) must also be communicated. A comprehensive “hand-off” allows the PACU staff to anticipate and plan for potential complications (1,2,4).

POSTANESTHESIA CARE

During a patient’s stay in the PACU, the PACU staff facilitates the process of emergence from anesthesia. Essential tasks include monitoring vital signs every 15 minutes; supporting respiratory status; pain management; administration of fluid and medication administration; treatment of postoperative nausea and vomiting (PONV); management of any problems or complications that may arise. The specific management of some of these issues will be subsequently reviewed. Many management issues that arise in the PACU are optimally managed using a team approach that includes the PACU nursing staff, anesthesiologist, surgeon, and/or consulting specialists.

PACU DISCHARGE

Another important function of the PACU staff is to evaluate readiness for discharge to the intensive care unit (ICU), inpatient unit, or home. Depending on the disposition plan, each patient may have a different set of criteria that are deemed appropriate. In caring for pediatric patients, who have significant variation in their cognitive and physiologic development, it is important to have well-trained PACU staff who is comfortable assessing pediatric patients for discharge.

Many institutions use a postanesthesia scoring system to document the patient’s vital signs and assess readiness for discharge (2,5). A common tool used in the pediatric population is the modified Aldrete Score that evaluates five areas: motor activity, respiration, blood pressure, consciousness, and oxygen saturation. Each category is given a score of 0, 1, or 2, with a maximum score of 10 (6). While these scoring systems are useful, discharge based strictly on predetermined criteria cannot replace the assessment of a well-trained PACU nurse and anesthesiologist. Each patient needs to be individually evaluated to ensure recovery of cardiorespiratory status: a stable airway and respiratory rate, adequacy of gas exchange, recovery of airway reflexes, stability of blood pressure, heart rate, circulation, and peripheral perfusion. Prior to discharge, patients should be awake or easily arousable, with adequate control of neuromuscular function and reasonable control of pain, nausea, and vomiting. Neuromuscular function after regional or peripheral nerve block should be assessed prior to discharge, and patients and families should be given appropriate instructions regarding pain control and recovery. Patients should be observed for an appropriate period of time (typically 20 to 30 minutes) after the last dose of narcotic administration. If reversal agents such as naloxone or flumazenil are used, the patient should be monitored for an appropriate time period to ensure that the narcotic or benzodiazepine effects have abated. Prior to discharge to the ward or ICU, an appropriate sign out should be given to the physician and nursing staff who will be taking over the care of the patient (1–3,7).

Patients who are planning to be discharged home have more strict criteria that include the following: (1) stable cardiovascular and respiratory status; (2) sedation has worn off, and patient is easily arousable with protective airway reflexes intact; (3) patient can talk (if age appropriate); (4) neuromuscular function has returned to baseline; (5) nausea and vomiting is well controlled, although PO intake in not required; (6) hydration state is adequate; (7) pain is controlled via oral medications. Patients with developmental delay should be evaluated based on their preanesthetic abilities and be as close to baseline levels as possible. It is reasonable to discharge infants and toddlers if easily aroused, even if not fully awake. Pediatric patients should be discharged with a parent or guardian who is given written instructions on the management of pain, surgical wound care, and directions on how to access to help 24 hours per day (1–3,5–7).

COMMON PACU CHALLENGES

GENERAL APPROACH TO THE PEDIATRIC PACU PATIENT IN DISTRESS

A child’s response to distress is significantly influenced by age, cognitive level, and individual variation. Determining the etiology and treatment for a child in distress is often challenging and time consuming. The lack of instant answers is often frustrating for caregivers, parents, and patients. Older children and adolescents may be able to verbalize their problems and concerns; preverbal toddlers and patients with developmental disabilities may respond to distress with crying and agitation; neonates and infants may respond with changes in facial expression, postural changes, and crying. Each patient needs to be individually evaluated taking into account the patient’s age, cognitive level, and behaviors to diagnose and treat problems. The presence of parents or caretakers in the PACU may be helpful in deciphering signs of distress. The preoperative evaluation can also be helpful in documenting a child’s response to distress or pain. Respiratory or cardiovascular instability must be ruled out in all pediatric patients in distress, because pain, emergence agitation (EA), or other problems can mimic cardiorespiratory compromise.

RESPIRATORY PROBLEMS

There is a higher incidence of respiratory complications in infants and children compared with adults due to decreased functional residual capacity (FRC), smaller airway size, and greater fatigability of respiratory muscles. While respiratory compromise may be obvious (i.e., tachypnea, obstruction, desaturation, or frank distress), respiratory distress in children can present as agitation, anxiety, unresponsiveness, or cardiovascular changes (tachycardia, bradycardia, arrhythmias, and hypo/hypertension) (1,3,7).

Upper Airway Obstruction

Upper airway obstruction after anesthesia is most commonly caused by decreased muscle tone of the hypopharynx and tongue after the administration of anesthetic agents. Other common causes include adenotonsillar hypertrophy (history of snoring should be ascertained on the preoperative assessment) or airway edema due to airway instrumentation or placement of an endotracheal tube. Signs and symptoms include stridor, respiratory distress with the use of accessory muscles, paradoxical respiratory effort, and, if severe enough, apnea. Depending on the etiology and severity of compromise, management requires stabilizing the patient while determining the etiology, reversible causes of the obstruction, and necessary treatment strategies (3,9).

Hypoxemia

There is a high incidence of hypoxemia in the early perioperative period in children recovering from anesthesia and sedation. Therefore, most pediatric anesthesiologists administer supplemental oxygen during transport and in the initial recovery period. Infants under 6 months of age, children with or recovering from a respiratory infection, and patients with preexisting pulmonary disease are at increased risk for postoperative hypoxemia. The first course of action is to ensure a patent airway and adequate gas exchange. The administration of supplemental oxygen can be challenging in children as they often do not tolerate a facemask; using creative techniques such as “blow-by” oxygen and enlisting parents in the effort can be very helpful.

Hypoventilation

Hypoventilation can cause hypercarbia, airway collapse, and atelectasis, which may lead to hypoxemia. This may be further exacerbated in patients who are not receiving supplemental oxygen. Furthermore, patients with preexisting pulmonary or neuromuscular disease are at increased risk for hypoventilation, hypoxemia, and upper airway obstruction.

Apnea of Prematurity

Postoperative apnea is seen in preterm infants, neonates, and former premature infants, which is exacerbated by anesthesia and opioid therapy for pain. Therefore, these children should be monitored closely and are usually admitted for close observation and monitoring. The management of the former preterm infant is described in Chapter 33.

Obstructive Sleep Apnea

While a comprehensive review of management of obstructive sleep apnea (OSA) is beyond the scope of this chapter, a large percentage of pediatric patients scheduled for ambulatory surgery undergo tonsillectomies for symptoms associated with adenotonsillar hypertrophy and/or OSA. The diagnosis of OSA is based on multiple criteria, including polysomnography (PSG) and patient history and physical examination. Patients with OSA are at increased risk for postoperative respiratory complications, including upper airway obstruction, apnea, hypoventilation, and hypoxemia. These patients should be monitored closely in the PACU and strongly considered for overnight admission for close observation and monitoring. The risk increases with increased degree of OSA, younger age (particularly <3), airway surgery, and other comorbidities. Patients with OSA have an increased sensitivity to opioids, and they must be used with extreme caution; patients with a history of severe preoperative hypoxemia (oxygen nadir <85%) during sleep have a 50% reduction in opioid requirements (3,8,9).

POSTOPERATIVE PAIN

Assessing pain in pediatric patients can be challenging as pediatric patients can have a wide variability in cognitive, verbal, and emotional responses depending on the patient’s age and developmental stage. Using an appropriate pain assessment tool is important in both assessing and treating pain. Several pain assessment tools have been used in pediatric patients and often rely on a combination of self-report, behavioral, and physiologic assessments (Chapter 10) (10,11).

Pain Assessment

Assessing pain in infants and children can be very challenging. Pain is subjective, and variation of responses to pain and distress has to be interpreted within the context of the cognitive and emotional development of the child. While the assessment and treatment of pain in the PACU should be prompt and vigorous, patients should be quickly evaluated to rule out life-threatening cardiorespiratory compromise or other sources of discomfort, and agitation should be considered: EA; disorientation; pain from other sources (e.g., tight cast), anxiety, thirst, and hunger.

Many age-appropriate pain assessment scales and systems have been validated using subjective and objective measures. The actual choice of measurement tool is not as important as its consistent and repeated use and effective communication of this information to other care providers.

  1.   Self-assessment is most reliable in patients who can effectively communicate. Self-report has also been shown to be effective with young children (3 to 7 years old) by the use of scales such as the revised Bieri or Wong–Baker Faces Pain Rating Scale; these scales use a series of five (Wong–Baker) or six (Bieri) faces to rate pain.

  2.   Behavioral and Physiologic scoring systems. For infants, young toddlers, and cognitively impaired children who cannot communicate, it is necessary to use a scale that assesses behavioral and physiologic parameters. The FLACC score assesses the following: face, legs, activity, cry, and consolability (10–18).

Pain Treatment

Optimal pain management is a continuum from the preoperative period through arrival in the PACU with the goal of providing optimal pain control while minimizing side effects. Pain management in pediatric and adult patients has distinct differences. Determining the source of a child’s discomfort may be difficult and certainly dependent on their cognitive and developmental level. They may or may not be able to understand or articulate their level of pain, and their discomfort may not be pain and can be difficult to sort out (e.g., anxiety, hunger, nausea, etc.). Because of the challenges with the evaluation of pediatric pain and/or discomfort, pain management should be carefully planned and individualized as part of the perioperative plan. Adequate pain control is best achieved with a plan that utilizes a multimodal approach. Based on the specifics of the child and the procedure, a combination of opioids, nonopioid analgesics, neuraxial anesthesia, and peripheral nerve blockade should be employed in order to provide adequate pain control as the child emerges from anesthesia and is discharged from the PACU (10–18).

Opioids

During the perioperative period, the use of intravenous opioids to control pain is common. It is important to balance short-acting and long-acting narcotics to provide the optimal pain relief for patients. For children admitted to the hospital, parenteral narcotics can be given using patient-controlled analgesia (PCA) for children starting at 6 to 8 years of age when they are cognitively ready. An option for younger patients and patients with developmental disabilities is “nurse-controlled analgesia” (NCA), a PCA pump administered by nurse proxy. For severe pain, a continuous narcotic infusion may be used. While receiving narcotics, all patients need to be monitored closely for adequacy of pain control and adverse side effects, especially hypoventilation and apnea. Of note, neonates, young infants (<1 month postgestational age), ex-premature infants under 55 to 60 weeks postgestational age, and children with certain preexisting diseases are at increased risk for respiratory depression due to increased sensitivity and decreased clearance and elimination of opioids. Doses need to be adjusted accordingly, and these patients should be considered for continuous apnea and pulse oximetry monitoring postoperatively (19–21).

Nonopiate Analgesics

While pediatric pain control is further discussed in Chapter 10, it is important to make mention of nonopiate analgesics that may improve pain control and minimize side effects. Such adjuncts may be used as sole analgesics in short or nonpainful procedures to provide adequate analgesia.

  1.   Acetaminophen. Acetaminophen may be administered in a variety of ways: oral (10 to 20 mg/kg), intravenous (10 to 15 mg/kg), and rectally (20 to 30 mg/kg). When using acetaminophen, it is important to communicate the dose and time to the PACU staff and subsequent caregivers to prevent an inadvertent overdose. Intravenous acetaminophen is becoming more widely used as part of opioid-sparing pain regimens. Of note, IV acetaminophen is Food and Drug Administration (FDA) approved for children older than 2 years of age, but may be used at reduced doses in children under 2 years of age (22–26).

  2.   Nonsteroidal anti-inflammatory drugs (NSAIDs). NSAIDs such as ketorolac (0.25 to 0.5 mg/kg) or oral ibuprofen (10 mg/kg) provide good pain control while avoiding respiratory depression. However, it is important to remember that these may adversely affect platelet and renal function and theoretically impair healing. Prior to administration of NSAIDs, the anesthesia and surgical team should evaluate the patient (27,28).

  3.   Dexmedetomidine. Recent studies suggest that dexmedetomidine (0.5 to 1 µg/kg) can reduce postoperative morphine requirements, particularly in patients undergoing tonsillectomy and adenoidectomy. As a caution, patients receiving 1 µg per kg did exhibit lower heart rates and blood pressure when compared to patients who received only morphine (29).

  4.   Local anesthetics. Additionally, local anesthetics provide good pain control with minimal side effects if delivered appropriately and below the toxic dose. Local anesthetics may be infiltrated at the site of incision, administered via a neuraxial block (i.e., epidural, spinal, or caudal block), or used in a peripheral nerve block. Patients who receive epidurals, caudals, or peripheral nerve blocks may be followed by a pain service for up to several days after surgery especially if catheters are placed for continuous infusions for longer-term pain management. It is important that these patients be monitored appropriately in the PACU for adequate pain control, sensation, and motor function. When patients are receiving an infusion, especially epidurals that may include narcotics, patients should be monitored for respiratory or cardiovascular instabilities. Peripheral nerve blocks may be administered as a single dose (pain control up to 6 to 12 hours depending on local anesthetic used) or as a continuous low-dose infusion that maintains nonopiate pain control. Prior to discharge, patients should be monitored for resolution of the blockade (e.g., return of sensation and motor function) and counseled regarding appropriate oral pain medication regiments (1).

EMERGENCE AGITATION

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