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10.6.2 Patient-controlled analgesia

PCA can provide safe and effective analgesia for children as young as 5 years old. Patient
selection depends on the ability of the child and carers to understand the concepts of PCA and
the availability of suitable equipment and trained staff. Recognition of potential complications
of PCA use was enhanced by providing set instructions for monitoring, and by acute pain
service (APS) support (Wrona et al, 2007 Level III‐2).
Efficacy
Compared with continuous IV opioid infusions, PCA provided greater dosing flexibility, and
similar analgesia. PCA has been associated with higher opioid consumption, but the incidence
of side effects has varied, depending on the PCA dosing parameters (Bray et al, 1996 Level III‐2;
Peters et al, 1999 Level II).
PCA can be particularly useful in children with altered opioid requirements. Postoperative PCA
morphine requirements in children with sickle‐cell disease were almost double those of non‐
sickle children (Crawford, Galton et al, 2006 Level III‐3). Intraoperative remifentanil was
associated with an increase in PCA morphine requirement in the 24 hours following scoliosis
surgery (Crawford, Hickey et al, 2006 Level II), possibly due to acute opioid‐induced hyperalgesia.
The PCA prescription
Morphine is the drug used most frequently in PCA. A bolus dose of morphine 20 mcg/kg is
a suitable starting dose and improved pain scores during movement when compared with
10 mcg/kg (Doyle, Mottart et al, 1994 Level II). The addition of a background infusion is more
common in children than adults, and 4 mcg/kg/hour is often recommended as doses of
10 mcg/kg/hour and above increased side effects (Howard et al, 2008). Although use of a
background infusion was associated with increased sleep disturbance in one audit (calculated
from the number of hours PCA presses were required), numbers were too small to fully
investigate the contribution of the degree of surgery (Kelly et al, 2006 Level IV).
Fentanyl is a useful alternative opioid, particularly for patients with renal impairment or those
experiencing morphine‐related side effects (Tobias & Baker, 1992 Level IV). Fentanyl PCA has
been used safely and effectively following neurosurgery (Chiaretti et al, 2008 Level IV), thoracic
surgery (Butkovic et al, 2007 Level III‐1) and tonsillectomy (Antila et al, 2006 Level II), and for acute
cancer‐related pain (Ruggiero et al, 2007 Level IV). In comparison with morphine, tramadol PCA
CHAPTER 10 Level II) and reduced nausea post‐tonsillectomy but at the cost of higher pain scores (Ozalevli et
provided minor improvements in time to extubation post cardiac surgery (Chu et al, 2006
al, 2005 Level II). Pethidine does not have any advantage over other opioids and neurotoxicity
from norpethidine (normeperidine) accumulation has been reported in a healthy adolescent
(Kussman & Sethna, 1998).
Nausea and vomiting occurs in 30% to 45% of children using morphine PCA and can be
reduced by prophylactic antiemetics (Carr et al, 2009 Level I). Adding antiemetics directly to
PCA solutions for children was not effective (Munro et al, 2002 Level II). Addition of a low‐dose
naloxone infusion did not impair analgesia, but decreased pruritus and nausea in
postoperative children treated with PCA (Maxwell et al, 2005 Level II) and also decreased
pruritus in children requiring morphine infusions during a sickle cell crisis (Koch et al, 2008
Level IV).

10.6.3 Nurse-controlled analgesia

In younger children and infants, ‘PCA’ pumps have been used for nurses to administer
intermittent bolus doses with or without a background infusion (ie nurse‐controlled analgesia
or NCA). This technique may increase ease of administration particularly prior to movement or
354 Acute Pain Management: Scientific Evidence