THE POST-ANESTHESIA CARE UNIT General Management
All children should be transported to the post-anesthesia care unit (PACU) in the lateral decubitus position with the head extended to provide an unobstructed airway; all children—other than absolutely healthy children having minor surgery—should receive oxygen or be monitored with SpO 2
during transport to PACU. Evidence suggests that decreases in SpO 2 during transport are most likely
due to airway obstruction; be alert to this possibility. However, administering oxygen while monitoring SpO 2
renders the oximeter an insensitive metric of hypopnea; respiration should be monitored by observing chest movements, mist in the facemask, or by feeling exhaled breathing. The anesthesiologist walks at the head of the bed facing forward to continuously observe and monitor the child. If the airway is in doubt, do not leave the 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. Transport with a self- infl ating bag or Mapleson D system at the ready is recommended. Children with a history of upper respiratory tract infections (URTI) are particularly at risk of airway problems. 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); describes the size tracheal tube used, distance of insertion, and ease of intubation; provides the timing and doses of antibiotics, analgesics, antiemetics, intravenous fl uid therapy, and blood loss and replacement; and describes the anesthesia technique including any complications and their management. Specifi c orders should be given for any continuing anesthesia care (e.g., continuous epidural analgesia).
Completes the anesthesia chart by recording the initial vital signs obtained by nursing staff in the PACU.
3. Completes postoperative (PACU) orders, including pain and anti-emesis orders, intravenous fl uids, and respiratory therapy.
4. Remains with the child until handover is complete and the PACU nurses accept care of the child.
In the PACU, every child receives oxygen via facemask 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 airway patency and the adequacy of ventilation. A child who still requires an oropharyngeal airway or tracheal tube may still need an anesthesiologist. 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. The progress of recovery should be documented with a post-anesthesia scoring system along with regular recording of vital signs. All children should receive oxygen until they can maintain an adequate SpO 2
in room air. SpO 2 should be
continuously monitored until the child is fully awake and ready for discharge. As soon as the child awakens, has stable vital signs and is free from pain, the
parents may be present at the bedside. This decreases the child’s anxiety in the PACU, reduces crying, and reduces the need for sedation. It also clarifi es whether the child is crying because of pain or the absence of a parent. 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 0.05–0.1 mg/kg IV or diazepam (0.1–0.2 mg/kg IV) may be administered.
Complications in PACU Laryngospasm
Laryngospasm may occur during emergence from anesthesia. During anesthesia, it may be treated as outlined elsewhere (Chap. 4 ) 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 Chap. 4 ). It should be managed by bag-mask ventilation with oxygen, maintaining positive airway pressure, and subluxation of the TMJ. Be prepared to administer either propofol or a short-acting muscle relaxant; reintubate the trachea if necessary and do not delay reintubation if desaturation progresses. Often a very small dose of succinylcholine (0.2 mg/kg) will relieve the laryngospasm.
Non-cardiogenic pulmonary edema may follow immediately upon relief of severe laryngospasm. If this occurs, treat with continued positive pressure ventilation, furosemide, fl uid restriction, and supplemental oxygen as indicated.
Postoperative Strido
Postoperative stridor caused by subglottic edema may occur especially after endoscopy, in children with a history of croup, those who were intubated as neonates, or after the unwise use of too large a tracheal tube diameter. Stridor is more common in children with Down syndrome and after surgery during which head movement occurred. Stridor usually appears within 30–60 min after extubation. The use of humidifi ed 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 min; this is usually effective. If racemic epinephrine is used, then the child should be observed for an extended period of time for possible rebound edema. 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 should be used
Emergence Deliriu
Delirium occurs most commonly but not exclusively in children 2–6 years of age after sevofl urane anesthesia, with a reported incidence up to 80 %. Delirium has also been reported after desfl urane or isofl urane. 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 delirium is usually transient, dissipating spontaneously within 10–20 min, without sequelae. The incidence may be attenuated by pretreatment with propofol, opioids, dexmedetomidine, clonidine, or NSAIDs (ketorolac). Diffi culty differentiating emergence delirium from postoperative pain has been addressed in part, with the introduction of a validated scale (Pediatric Anesthesia Emergence Delirium scale) to measure delirium in children. Treatment in the PACU may require small doses of propofol or fentanyl
Shivering and Rigidit
Shivering and rigidity may occur during recovery from anesthesia, sometimes associated with hypothermia and may at other times, occur in normothermic children. This may increase the metabolic rate and oxygen requirement and is very undesirable after some procedures (e.g., orthopedic). It should be treated with low-dose intravenous meperidine (Demerol) (0.25 mg/kg IV) or dexmedetomidine (0.5 μg/kg IV slowly), which may eliminate the shivering
Nausea and Vomiting Postoperative nausea and vomiting (PONV) is troublesome and a leading cause of delayed discharge from the hospital or, more rarely, of unplanned admission of the day surgery patient. The incidence of PONV can be signifi cantly 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 anti-infl ammatory drugs [NSAIDs]) or regional analgesia whenever possible. However, pain itself may cause PONV—so ensure analgesia. Regional analgesia is ideal.
2. Administer large volumes (up to 30 mL/kg) of balanced salt solution intraoperatively.
3. Avoid oral fl uids postoperatively; wait until the child asks for them or is thirsty. 4. Do not rush to mobilize the child, especially after eye surgery.
When nausea and vomiting can be anticipated (e.g., strabismus surgery,
adenotonsillectomy), 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 fl uids (20–30 mL/kg), and by prophylactic multimodal antiemetic therapy (dexamethasone and a serotonin-receptor antagonist, such as ondansetron). In children with unexpected nausea and vomiting or when the above therapies fail, rescue medication with an antiemetic drug is necessary (Table 7.1 ). Ondansetron is the most effective antiemetic for PONV. Dexamethasone is
not a rescue antiemetic. If it was not given intraoperatively, it may be given postoperatively but should be given over 5 min to reduce the risk of perineal irritation. Dimenhydrinate and metoclopramide are both moderately effective antiemetics and cause little sedation; they may be used for protracted vomiting in PACU. Droperidol in doses adequate to combat nausea and vomiting may cause sedation, with delayed recovery and discharge.
Table 7.1 Antiemetic drug doses for children Dexamethasone
75–150 μg/kg (maximum 8 mg) Ondansetron
Dimenhydrinate Droperidol
Duration of Stay in PACU
Children remain in the PACU until they are fully awake and recovered from the effects of anesthesia. As a general rule, a minimum stay of 30 min 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
50–100 μg/kg (maximum 4 mg) 0.5 mg/kg (maximum 25 mg) 10–15 μg/kg (maximum 1.25 mg)
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 with lower respiratory tract signs and persistent desaturation may require deepbreathing and coughing exercises and chest physiotherapy. 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, specifi c written clinical criteria should be documented. If an anesthetic complication occurs, the child must be re-evaluated by the anesthesia team before discharge from PACU. If the child receives IV opioids in the PACU, they should be monitored for an additional 30 min to ensure adequacy of ventilation before discharge.
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 unmodifi ed 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 diffi cult 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.
Currently, we know that all children can experience pain, we are better equipped to assess the severity of the pain (pain scoring systems), and we have better means to control pain (PCA, nerve blocks, continuous catheter techniques). Postoperative pain management should be planned during the preoperative evaluation and discussed with the child and parents; consent for additional procedures should be obtained where appropriate. For outpatients, it is most important that the parents are well instructed in the management of pain when the child arrives home:
1. Analgesic drugs must be administered before pain becomes signifi cant and repeated regularly by schedule rather than waiting for pain to be a problem. The only exception to this approach would be the child with OSA where opioids could pose a threat to their safety; techniques such as alternating acetaminophen/ibuprofen at fi xed intervals are recommended.
2. The “analgesic gap” as regional analgesia wears off must be anticipated (most often manifest by the child becoming irritable or quiet) 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 and the parent instructed in its use. Written instructions should be provided to the parents and discussed with them.
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 fl exion 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 ). Older children may be asked to report their pain level using one of a variety
of VASs, such as the Wong-Baker FACES Pain Rating Scale (Fig. 7.1 ). They may also be asked to rate their pain on a color scale or to report it by coloring their pain on a body outline. Adolescents can be assessed with the use of standard adult self-report scales. Note, however, that at this age psychological and emotional factors may infl uence the response much more than in younger children. When treating pain at any age, it is essential to monitor the response to therapy
with an objective scoring system. Pain scores should be regularly recorded on the patient’s vital signs chart.
Table 7.2 A pain scale for preverbal and nonverbal infants (FLACC Scale) Score
Category Face
Legs Activity Cry 0
No particular expression or smile
Normal position or relaxed
Lying quietly, normal position, moves easily
No cry (awake or asleep)
1
Occasional grimace or frown, withdrawn, disinterested
Uneasy, restless, tense
Squirming, shifting back and forth, tense
Moans or whimpers, occasional complaint
Consolability Content, relaxed Reassured by occasional touching, hugging, or being talked to; distractable
2
Frequent to constant quivering chin, clenched jaw
Kicking or legs drawn up
Arched, rigid, or jerking
Crying steadily, screams or sobs, frequent complaints
Diffi cult to console or comfort
Reproduced with permission of Merkel SI et al: The FLACC: A behavioral scale for scoring postoperative pain in young children. Pediatr Nurs 23:392, 1997
217
Fig. 7.1 Wong-Baker FACES pain rating scale. (© Reproduced with permission of Dr. Donna L. Wong and Mosby Inc. Wong DL, et al. ( eds ): Nursing Care of Infants and Children, 6th ed. St. Louis, Mosby-Year Book, 1999 )
POSTOPERATIVE PAIN
Postoperative pain has adverse physiologic and psychological effects. Optimal postoperative pain relief minimizes the metabolic rate for oxygen, reduces cardiorespiratory demands, promotes early ambulation, and speeds recovery. In addition, postoperative emotional disturbance is reduced if pain is well controlled.
Systemic Analgesic Drugs
After minor procedures, when no regional or local analgesia regimen is possible, the use of a systemic analgesic is indicated. Dosages in common use are listed in Table 7.3 . Meperidine is no longer recommended for perioperative analgesia in children because of the potential for seizures associated with its metabolite normeperidine; its only indication is to treat shivering. The appropriate drug should be chosen for the magnitude of the pain, and a
satisfactory effect should be confi rmed. It is preferable to administer the fi rst analgesic dose before the child emerges from general anesthesia—for example, for tonsillectomy give 0.025–0.05 mg/kg IV morphine during surgery (if no OSA is present), and for minor superfi cial surgery give (Perfalgan) acetaminophen, 15 mg/ kg IV or ~40 mg/kg PR, after induction of anesthesia. Do not cut suppositories of acetaminophen (or any other drug) as the acetaminophen may not be evenly distributed throughout the suppository. Remember that peak blood levels are achieved 60–180 min after rectal administration, so the suppository must be administered immediately after induction and this route is not appropriate for brief procedures; multiple suppositories with several strengths may be simultaneously administered to achieve the desired ~40 mg/kg PR dose. Avoid intramuscular injections in awake children; give analgesics by the intravenous, rectal, or oral route.
Mild Analgesics and NSAIDS Acetaminophen . Acetaminophen is a mild analgesic and antipyretic drug, but it
provides good analgesia and antipyresis after minor procedures, especially if given before the surgery. It is considered safe in neonates, but metabolism and elimination are delayed in neonates compared with adults, so repeat doses should be given at 6- rather than 4-h intervals. Excessive doses can cause hepatic failure; the total
Table 7.3 Common dosages for systemic analgesics
For minor procedures Acetaminophen, 10–20 mg/kg PO, 30–40 mg/kg PR loading dose followed by 20 mg/kg q6h, maximum 90–100 mg/kg/24 h; 15 mg/kg IV for children (7.5 mg/kg for infants <10 kg) Ibuprofen, 5–10 mg/kg PO Ketorolac a , 0.5 mg/kg IM or IV to a max. of 15 mg for <50 kg and 30 mg for >50 kg Tramadol a , 1–2 mg/kg q6h
For major procedures Morphine, 0.1–0.2 mg/kg IV q2–4 h Hydromorphone, 5–15 μg/kg IV q4–6 h Oxycodone a , 0.1–0.2 mg/kg po q4–6 h Hydrocodone a , 0.05–0.1 mg/kg po q4–6 h
a These opioids are subject to CYP2D6 polymorphisms that may result in drug overdose (in ultrarapid metabolizers) or inadequate analgesia (in poor metabolizers)—see text for discussion
daily dose should not exceed 90–100 mg/kg (maximum daily dose for IV acetaminophen in children is <75 mg/kg). Make sure that clear instructions are given to parents about dosage after the child is discharged . Hepatic damage has been reported after excessive doses of acetaminophen or when given to debilitated children. After major surgery, acetaminophen combined with opioids reduces the dose of the latter, thereby reducing the risk of respiratory depression. Acetaminophen does not affect surgical bleeding. Oral acetaminophen dosing is 10–15 mg/kg q4–6 h; IV acetaminophen (Perfalgan) is given q6h to infants <10 kg as 7.5 mg/kg and to children 11–50 kg as 15 mg/kg IV. Children >50 kg may receive 1 g IV q6h. IV acetaminophen should be infused over 15–20 min; the dosing in infants should be carefully checked as a number of cases of several-fold overdoses have been reported.
Diclofenac
Diclofenac has been widely used in children and may be administered orally, intravenously or rectally; it is currently under development for parenteral use in children in North America. It is reported to be effective for pain control after minor surgical procedures. Suggested pediatric dosing is 0.3 mg/kg IV, 0.5 mg/ kg rectal, and 1 mg/kg oral every 8 h. After tonsillectomy, it reduces the need for opioids and hence reduces PONV. There is greater bioavailability after rectal administration than with the enteric-coated formulation. It does not signifi cantly affect bleeding or clot strength in children after tonsillectomy. The smallest PR dose currently available in the United States is 50 mg.
Ibuprofen
Ibuprofen , an NSAID, may be given by either the oral or rectal route, 4–10 mg/ kg every 6 h. It reduces the child’s opioid requirements postoperatively. However, ibuprofen can cause gastrointestinal upset (nausea, vomiting, diarrhea) and decrease platelet aggregation, which could increase bleeding.
Ketorolac
Ketorolac is another NSAID; its potent analgesic effects may rival those of morphine without the respiratory depressant effects of the latter. When given before surgery, ketorolac 1 mg/kg IV appears to provide postoperative analgesia comparable to 0.1 mg/kg of morphine; however, this dose is now considered excessive. The recommended IV dose is 0.5 mg/kg to a maximum of 15 mg in children <50 kg and 30 mg in children >50 kg. In common with other NSAIDs, ketorolac inhibits platelet aggregation and is not recommended when bleeding may be a problem. Impaired bone healing after ketorolac remains controversial. Other serious but uncommon potential side effects include gastrointestinal hemorrhage, interstitial nephritis, and acute renal failure. Once hemostasis has been
achieved, it is our practice to ask the surgeon if ketorolac can be administered given its potential negative effects on platelet function and bone healing. Celecoxib
Recent evidence identifi ed a reduction in the morphine requirements in children undergoing tonsillectomy, after 6 mg/kg oral Celecoxib was administered preoperatively followed by 3 mg/kg q12h. There was no effect on postoperative bleeding. Celecoxib may fi nd a role in perioperative pain management in children.
Opioid Drugs
Morphine . Morphine remains a most useful drug in the management of postoperative pain. It produces effective analgesia together with sedation and a useful degree of euphoria. For children, it is preferably administered intravenously in a dose of 50–100 μg/kg every 7–10 min until comfortable or for ongoing pain, by continuous infusion/PCA (see later discussion). Codeine . Codeine has been used to treat moderate pain. It may be given intramuscularly or orally, but never intravenously as severe hypotension may result. For most children, the usual dose of codeine is 1–1.5 mg/kg IM or PO (maximum, 60 mg). Codeine has been considered a safe drug for infants and children, but respiratory depression similar to that associated with morphine may occur, especially after repeated doses. There are some populations that carry polymorphisms of CYP2D6 isozyme that may either prevent or reduce the pain relief from codeine or convert codeine to morphine so rapidly that respiratory depression may suddenly occur (see Chap. 3 for details). Codeine is used much less frequently since reports of deaths after tonsillectomy in children with OSA have appeared and the FDA since issued a black box warning on its use after tonsillectomy (see Chap. 3 ). This drug is no longer recommended for routine use or postoperative analgesia in children. Hydromorphone ( Dilaudid ). Hydromorphone is a long-acting opioid analgesic that is 5–7 times more potent than morphine in the IV form. Thus, the IV analgesic dose in children is 5–15 μg/kg. Its elimination half-life is 2.5 h. Hydromorphone may be given as an alternative postoperative analgesic to morphine. Hydrocodone (0.05–0.1 mg/kg) is also a long-acting oral opioid commonly used for analgesia. This drug is metabolized by CYP2D6 to the active metabolite hydromorphone and subject to the same polymorphism issues as codeine that may result in both drug overdose in children who are rapid metabolizers and minimal analgesia in those who are slow metabolizers. Therefore, we recommend it with caution. Oxycodone ( Oxycontin ). Oxycodone (the acetaminophen containing version
of oxycontin) is most commonly prescribed as an oral analgesic, but is also approved for IV, IM, and sublingual routes in some countries. For chronic pain,
a sustained release oral preparation is also available. Single doses of oxycodone via all routes are 0.1–0.2 mg/kg every 6 h. It has been used in older children to transition from PCA to oral analgesics. Its side effect profi le is similar to that of morphine. However, it too is subject to the problems associated with polymorphisms of 2D6, as the active form of oxycodone is its metabolite, oxymorphone. Tramadol . Tramadol is a synthetic opioid with limited dosing recommendations in children (from studies outside of North America); a dose of 1–2 mg/kg IV provided good pain relief in children after tonsillectomy and may be useful in children with OSA. It has an elimination half-life of 6–7 h in adults. In North America, it is only available in an oral formulation and indicated only for adults. Tramadol is also subject to variable metabolism due to the CYP2D6 polymorphisms that could potentially lead to accumulation of active metabolites.
Continuous Opioid Infusions A continuous infusion of morphine, using a dilute solution administered by a
designated patient-controlled analgesia (PCA) pump provides for a constant level of analgesia with good sedation and is appropriate for many children after major surgery. The child must have close nursing supervision and be monitored by pulse oximetry. The dose administered should be frequently titrated against the observed and recorded pain level. Recommended doses for continuous infusions of morphine.
1. Children >1 year: Loading dose, 0.1 mg/kg IV; infusion, 10–30 μg/kg/h For some children, the loading dose may have to be repeated to establish an initial satisfactory level of analgesia.
2. Infants <1 year: Loading dose, 0.05 mg/kg IV; infusion, 5–15 μg/kg/h Infants receiving a morphine infusion should be carefully monitored during the infusion and for 24 h after the infusion is discontinued to detect respiratory depression.
Reduced infusion rates may be adequate after cardiac surgery, especially in
children who are receiving vasopressors, when the clearance rates for morphine are reduced.
Patient-Controlled Analgesia
Children older than 5 or 6 years of age are capable of using a PCA system to obtain excellent pain relief. Children may especially benefi t from PCA; they do not have to ask for pain relief and can be “in control.” Most children are familiar with computer games and have no problem mastering the principles of PCA. It is important that a safe regimen be established and that both child and parents be reassured that the system has an appropriate lockout time and total dosage safeguards. The parents (and otherp adults) should be warned not to trigger the
Table 7.4 Dosages for patient-controlled analgesia with morphine
For orthopedic surgery Initial bolus doses
PCA bolus dose Lockout period
Background infusion For general surgery
For orthopedic surgery For spinal surgery
Maximum hourly dose
0.1–0.2 mg/kg IV until settled 10 μg/kg
7–10 min
0–20 μg/kg/h 0–25 μg/kg/h 0–40 μg/kg/h 0–100 μg/kg
PCA for the child. Recent evidence, however, suggests that parents or nurses can effectively and safely manage PCA for a child who is unable to do so for age, cognitive, or physical reasons. If such an approach is used, an educational program for the surrogate user must be delivered successfully before they are allowed to participate. Always be aware that overdose is a potential complication when well-meaning parents are allowed to push the PCA button . All children being treated with opioids should have a loading dose. Whether a
background infusion is used to supplement boluses is controversial, but in children a continuous infusion of a small dose of morphine complemented with PCA supplements may give the best results in terms of both pain control and sleep pattern. The regimen used should be tailored to the type of surgery; after orthopedic
surgery, children have greater morphine requirements than after general surgery, and after spinal surgery, the requirements are greater still. It is convenient to adjust the background infusion rate to suit the type of surgery (Table 7.4 ). Side effects of PCA include the following:
1. Nausea and vomiting : This may be troublesome and may require a reduction in the opioid dosage and administration of promethazine (0.25–0.5 mg/kg), ondansetron (0.1 mg/kg up to 4 mg), or other antiemetics. Be aware that promethazine may cause sedation. Low-dose naloxone infusions (0.25 μg/ kg/h) have attenuated opioid-associated side effects.
2. Excessive sedation : Monitor children carefully and have naloxone ready to treat excessive narcosis and respiratory depression. It may be prudent to keep naloxone and a bag-mask oxygen source at the bedside. Be alert to the possibility
that someone who is unaware that the child is receiving a PCA may order a “stat dose” of another analgesic or sedative drug and thereby produce respiratory depression. Write specifi c orders for children with PCA pumps that they are to have no additional drugs without the knowledge of the PCA team.
Regional Analgesia for Postoperative Pain
The pain that occurs after many procedures can be effectively treated by regional analgesia, and this should be used whenever possible. Frequently, no additional drugs, or at the most, only mild analgesics (e.g., acetaminophen) will be required. Thus, the side effects of opioids are avoided and the child rapidly returns to full activity after minor surgery. These blocks are performed using surface landmarks (caudal epidural block), nerve stimulation, or preferably under ultrasound guidance (Table 7.5 ). The use of ultrasound increases success rates, decreases dose
Table 7.5 Suggested dosages for epidural/caudal blocks Bupivacaine
Loading dose (0.25 %)
Infusions a Children Infants
Neonates b Ropivacaine
Loading dose (0.2 %)
Infusions a Children
Neonates-6 monthsb
PCEA (0.1 or 0.2 %) Bolus dose
Lockout interval Background infusion
Levobupivacaine Loading dose (0.25 %)
Infusion a (0.0625–0.125 %)
2-Chloroprocaine Loading dose (1–3 %): Infusion a (1–3 %)
Morphine Single dose
Fentanyl Infusion
PCEA
Loading dose Bolus dose
Lockout interval Background infusion 0.5 mL/kg
0.4–0.5 mg/kg/h for (0.125 % at 0.3 mL/kg/h) c 0.25 mg/kg/h for (0.125 % at 0.3 mL/kg/h) c 0.2 mg/kg/h (0.1 % at 0.2 mL/kg/h)
0.5 mL/kg
0.4 mg/kg/h 0.2 mg/kg/h
0.1 mg/kg 10 min
0.1 mg/kg/h
0.5–1.0 mL/kg 0.3 mL/kg/h c
10–20 d mg/kg 0.3–1 d mL/kg/h
0.030 e (range of 0.01–0.10) mg/kg preservative-free morphine in up to 15 mL preservative-free saline
1–2 μg/mL @ 0.3 mL/kg/h without local anesthetic 1.4 μg/kg
0.5 μg/kg 15 min
0.5 μg/kg/h
a Start infusion immediately after the loading dose b Limit infusions to 48 h
c No benefi t adding fentanyl to this solution d Larger doses should be used with epinephrine and with caution in neonates (max. dose reported is
60 mg/kg) e
Most effective and commonly used dose; larger doses generally increase side effects
requirements, and reduces the number of needle passes needed. Provision should be made, however, for transition to systemic analgesics after the block dissipates. Studies have shown that signifi cant pain may occur at this time, especially in outpatients. The parent should be carefully instructed to administer an analgesic drug (e.g., acetaminophen or other analgesic) in anticipation of this need. After major surgery, appropriate nerve blocks (e.g., intercostal nerve block) using local analgesic drugs may reduce the dose of opioids and facilitate earlier mobilization. Here, epinephrine should be considered. The possibility that a regional block established before the surgical incision
(preemptive analgesia) may modulate total postoperative pain by preventing biochemical changes (“windup”) within the central nervous system is appealing, but the results of well-designed studies have been disappointing. Regional blocks performed before the surgical incision do provide intraoperative analgesia, thus reducing the dose of general anesthetic drugs required. This reduction in anesthetic requirement indicates that the block is well established before emergence. Studies of complications after pediatric regional analgesia procedure
strongly suggest that peripheral nerve blocks are associated with fewer complications than neuraxial blocks. Hence, whenever there is a choice, a peripheral nerve block should be performed. Peripheral nerve and neuraxial blocks as well as their complications and treatments are detailed in Chap. 5 . s .