Patient Controlled Analgesia PCA

  • This pain management guideline was written by the staff of the Children's Pain Management Service for the Royal Children's Hospital, Melbourne.

    This guideline may NOT be suitable for use in other institutions.

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    Nurse competencies

    • All Registered Nurses caring for patients receiving PCA should complete and pass their opioid competency annually. 
    • If Registered Nurses are regularly caring for patients with PCA they should complete the PCA competency also.

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    • PCA is used for the management of moderate to severe pain when inadequate analgesia would result from oral analgesia or intermittent IV morphine boluses.
    • The child must have the cognitive ability to understand the concept PCA and is willing to self-manage analgesia.
    • Lack of normal hand function does not prevent patients from using PCA. A number of alternate handsets are available.

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    Contraindications to PCA

    • If the child is unable to understand the concept of PCA or they do not wish to control their own analgesia, a nurse controlled opioid infusion would be more suitable.

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    Prescription and program of PCA

    • PCA is a specialised analgesia technique and is managed by CPMS. 
    • Most patients are commenced on PCA in the recovery room. For other patients requiring PCA a referral needs to be made to CPMS by paging 5773 (24 hours) and completing an inpatient electronic referral. The referrer needs to ensure that the patient's primary consultant has approved of CPMS involvement. 
    • ONLY CPMS and Anaesthesia staff may prescribe PCA. For safety reasons ONLY Recovery or CPMS staff may program the PCA infusion pumps.
    • Please contact CPMS to program the pump during office hours or recovery after hours
    • Morphine is the preferred opioid in most circumstances. Fentanyl or hydromorphone are alternative choices. 
    • The PCA infusion is prescribed according to the PCA prescription guidelines . 

      Opioid dilution for PCA

      Less than 50kg: 0.5 mg / kg diluted to a total volume of 50 mL with normal saline
      Bolus dose:  2 mL = 20 microgram / kg 
      *Background: 0.5 mL / hr = 5 microgram / kg / hr

      More than 50kg: 50 mg diluted to a total volume of 50 mL with normal saline
      Bolus dose: 1 mL = 1 mg
      *Background: 0.5 mL / hr = 0.5 mg / hr

      Less than 50kg: 15 microgram / kg diluted to a total volume of 50 mL with normal saline
      Bolus dose: 1 mL = 0.3 microgram / kg 
      *Background: 1 mL / hr = 0.3 microgram / kg / hr

      More than 50kg: 750 microgram diluted to a total volume of 50 mL with normal saline
      Bolus: 1 mL = 15 microgram
      *Background:  1 mL / hr = 15 microgram / hr

      Less than 50kg: 0.1 mg / kg diluted to a total volume of 50 mL with normal saline
      Bolus dose: 1 – 2 mL = 2 – 4 microgram/kg 
      *Background: 0.5 – 1 mL / hr = 1 – 2 microgram/kg/hr

      More than 50kg: 6 mg diluted to a total volume of 50 mL with normal saline
      Bolus dose: 1 mL = 120 microgram
      *Background: 0.5 – 1 mL / hr = 1 – 2 microgram/kg/hr

      Lockout 5 minutes 
      Background infusion
      * Rarely required 

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    PCA set up

    • The PCA syringe must be prepared in accordance with RCH medication policy and labelled clearly with a blue intravenous additives label.
    • PCA infusion pumps (Alaris P5000 PCA) must be used for all PCA infusions.
    • The PCA infusion line should be clearly labelled with a blue IV opioid label at the 3-way-tap where the PCA line meets the maintenance line.
    • 50 mL Braun Omnifix syringes are used for PCA, together with 180 cm minimum volume extension tubing.
    • A 3-way-tap at the syringe end of the opioid infusion line is not required.
    • The two authorised persons who make up each PCA syringe must sign the record of infusion on the Patient Controlled Analgesia prescription.
    • Syringe and lines should be changed every 72 hours or more often depending on individual unit policy or the patient's medical condition.
    • Keys for the PCA infusion pumps are kept with the ward drug keys on every ward. The operating theatre recovery room also has a set of PCA keys.

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    PCA delivery

    • To avoid the IV occluding between PCA tries, the patient should have maintenance IV fluids (with a minimum infusion rate of 5 mL/hr) running through an infusion pump (IVAC or similar). No anti-reflux valves are required if an infusion pump is used. 
    • The volume infused should be checked every hour and documented on the fluid balance chart. 
    • The treatment for opioid overdose is the opioid antagonist naloxone (Narcan). Naloxone is available in the ward/unit drug cupboard and on the ward/unit resuscitation trolley. 
    • The naloxone dose is available in 3 dose ranges: 1 microgram/kg for opioid induced pruritus and urinary retention, 2 microgram/kg for excess sedation and 10 microgram/kg for resuscitation.

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    Concurrent drugs

    • When opioid infusions are used, NO ORAL/ RECTAL/ INTRAVENOUS opioids or sedative agents should be given without prior consultation with CPMS or an anaesthetist.
    • Paracetamol, ketamine, local anaesthetics, tramadol and NSAIDs may be used concurrently with PCA infusions and may help to reduce opioid consumption and associated side effects.

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    • If the patient is receiving other medication that may cause sedation (e.g. antihistamines, benzodiazepines or anticonvulsants), the patient may be at increased risk of sedation and respiratory depression.
    • Prolonged administration of opioid infusions and impaired liver and/or renal function may alter drug elimination with ALL opioids and possibly result in drug accumulation and toxicity.   
      • The morphine metabolite M3G causes CNS disturbances (including myoclonus and tremor) and the morphine metabolite M6G is a potent analgesic. Both these metabolites may accumulate in patients receiving long-term morphine infusions or patients with renal impairment.
      • The hydromorphone metabolite H3G may accumulate in patients receiving long-term hydromorphone infusions or patients with renal impairment. H3G can cause CNS disturbances (including confusion, tremor and agitation).  
      • Prolonged fentanyl infusion may result in drug accumulation and potential increase in opioid related side effects.
    • Development of opioid tolerance with long-term administration of opioids may require the opioid dose to be increased.
    • Careful tapering of doses is important when weaning long-term opioids to avoid opioid withdrawal.

    Parents and PCA

    • It is important that the child's parents understand the concept of PCA, so they can support their child in its use.
    • The child's parents must NOT push the PCA button for their child, but may encourage their child to use it as required.

    Patient review

    • CPMS reviews patients twice daily on week days and once daily on weekends and public holidays.
    • If analgesia is inadequate or the patient is experiencing side-effects, CPMS must be called to review the patient.
    • CPMS can be contacted at all times on pager 5773.


    The following observations should be recorded on the general observation chart:

    • Sedation score, respiratory rate and heart rate: 1 hourly until the PCA is ceased. [The need for less frequent observations for patients receiving long-term PCA should be discussed with CPMS.] It is important to accurately assess sedation during wake and sleep periods
    • Pain score: 1 hourly while awake (using developmentally appropriate scale e.g. Wong-Baker Faces scale, Numeric scale, FLACC scale or PAT score).
    • Vomiting score: 1 hourly  for the first 12 hours, then 4 hourly as indicated.
    • Pulse oximetry: if indicated 

    Indications for pulse oximetry:

    Pulse oximetry MUST BE implemented and used continuously in high-risk patients with:

    • University of Michigan Sedation Scale (UMSS)

       0 Awake and alert
       1 Minimally sedated: may appear tired/sleepy, responds to verbal conversation and/or sound 
       2 Moderately sedated: somnolent/sleeping, easily aroused with light tactile stimulation or simple verbal command
       3 Deep sedation: deep sleep, arousable only with deep or significant physical simulation
       4 Unarousable
       S Patient is sleeping
      UMSS sedation score > 2
    • Significant cardiorespiratory impairment
    • Sleep apnoea, snoring or airway obstruction
    • Spot oximetry less than 94% SaO2

    or patients receiving:

    • Supplementary oxygen
    • Concurrent sedative agents

    Clinical indicators for 'spot' pulse oximetry are:

    • Tachypnoea or bradypnoea
    • Respiratory distress
    • Pallor or cyanosis or impaired oxygenation
    • Confusion or agitation
    • Hypotension
    • Nurse concern
    • PCA use: good and bad tries and total mg, recorded hourly on the PCA flowsheet  
    • The effectiveness of the analgesia should be recorded in the Nursing Progress notes.

    CPMS should be called if pain relief is inadequate after more than 5 good tries per hour for three hours.

    Any observations outside normal values for age should be reported to CPMS +/- the primary treating team.

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    • CEASE the PCA
    • CEASE all other infusions that could be contributing to sedation
    • Attempt to rouse the patient
    • Call 777 [MET team] if appropriate
    • If apnoeic: administer bag & mask ventilation with 100% oxygen
    • If breathing: maintain airway, monitor oxygen saturations and administer oxygen
      via face mask at 8 L/min
    • Check circulation. If pulseless: commence chest compressions
    • Administer naloxone per instructions on the attachment chart if opioid toxicity is suspected
    • Call CPMS for urgent review

    Ceasing the PCA

    • The decision to cease the PCA should ideally be made in consultation with CPMS.
    • Most patients self-wean off PCA, using it less as their pain decreases.
    • Oral opioids may be administered immediately after the PCA is ceased.
    • The date and time of ceasing the PCA must be recorded on the Patient Controlled Analgesia prescription
    • Any remaining opioid must be disposed of according to the RCH Drugs of Addiction policy.
    • The PCA infusion pump must be returned to Recovery when it is no longer required.

    First version written July 1998, last Updated May 2019