Indicaciones de la PCA para el dolor agudo

Se puede definir como el dolor de inicio reciente, con perspectivas de duración limitada y que, generalmente, tiene una causa identificable relacionada directamente con la aparición del dolor. Su origen puede ser en estructuras cutáneas, somáticas profundas o viscerales, por lo que el diagnóstico y la evaluación en la intensidad del dolor es un capitulo fundamental, que va a condicionar la estrategia terapéutica a seguir. Tradicionalmente se distinguen cuatro grados de intensidad del dolor; leve, moderado, intenso e insoportable, la potencia analgésica guarda relación directa al grado de intensidad del dolor.
Los cuadros de dolor agudo más frecuentes y que son subsidiarios de un correcto tratamiento con PCA. Son; Dolor postoperatorio, dolor obstétrico, y dolor agudo de otras etiologías que se pueden apreciar en la urgencia de cualquier hospital (politraumatizado, litiasis, quemados, etc.).

Dolor Postoperatorio. Se trata en otro apartado de la pg. de la web.

Dolor Obstétrico . Es uno de los supuestos en que un sistema de perfusión va a ser de gran utilidad por que puede cubrir las necesidades analgésicas aunque la duración del parto sea prolongada y por que nos permite delegar en otro personal sanitario la vigilancia del acto (siempre bajo la supervisión del profesional).

¿Cuáles son las características exigidas a un sistema de infusión en Obstetricia? Fundamentalmente dos:

1-Seguridad; teniendo en cuenta que es un proceso en el que el médico no suele estar presente en todo momento es necesario un sistema en el que la parturienta o los que le rodean no puedan manipular para evitar sobredosis o mayores problemas.
2-Versatilidad; pues el parto es una secuencia en la que el nivel álgico no es estable y será preciso adecuarse a ello mediante la posibilidad de administración de dosis extras o de cambios en la infusión.

Las dosis anestésicos, etc. en la sección de protocolos.

Dolor Agudo de otras Etiologías . Es subsidiario de la administración de una PCA, todo cuadro álgico que se le presuponga en el tiempo, una duración suficiente para instaurar un tratamiento analgésico sin interrupción, generalmente no hay potencial para cumplir estos requerimientos y es preciso escoger unas patologías entre las que se encuentran:

-Quemaduras extensas.
-Cólicos nefríticos complicados.
-Traumatismos.
-Movilizaciones precoces, etc.

El modelo de bomba de infusión es útil para el tratamiento del dolor agudo, crónico (en el tiempo de prueba de la idoneidad de la técnica de infusión), y para el tratamiento con antibióticos o quimioterapia en pacientes oncológicos por vía intravenosa, así como la administración de otra medicación en régimen ambulatorio que el paciente necesite, y que no sea posible su desplazamiento o se estime el beneficio de recibir el tratamiento en casa.

Ver artículos:

Walker P, Neuhauser MN, Tam VH, Willey JS, Palmer JL, Bruera E, Prince RA. Administración subcutánea de cefepime. J Pain Symptom Manage. 2005;30(2):170-4.

Cox JA, Journal of Infusion Nursing, 28(2), Home infusion therapy: Essential characteristics of a successful education process: grounded theory study., Mar 1, 2005, pp 99-107.

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.

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.
-Click here to access RCH nurse competencies

INDICATIONS

-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 and a breath-triggered switch are available.

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.

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 consultation report sheet (MR2). 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.
-Morphine is the preferred opioid in most circumstances. Fentanyl or hydromorphone are alternative choices. Pethidine is NOT routinely used due to the concern for nor-pethidine toxicity. In some circumstances patients may have pethidine prescribed but this should only be for a short duration (generally less than 48 hours).
-The PCA infusion is prescribed according to the guidelines on the Patient Controlled Analgesia attachment. This attachment is only valid if attached to a current medication chart (MR52).
-If the prescription differs from the guidelines the designated box must be ticked.

PCA SET UP

-The PCA syringe must be prepared in accordance with RCH medication policy and labelled clearly with an intravenous additives label.
-PCA infusion pumps (Graseby 3300 PCA or 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 attachment.
-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.

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 2 dose ranges: 2 microgram/kg for excess sedation and 10 microgram/kg for resuscitation.

CONCURRENT DRUGS

-When opioid infusions are used, NO ORAL/ RECTAL/ INTRAVENOUS OR INTRAMUSCULAR 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.

PRECAUTIONS

-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).
Pethidine infusions may result in accumulation of the toxic metabolite nor-pethidine, which can cause CNS disturbances (including confusion, tremor and convulsions).
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.

OBSERVATIONS

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.]
-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:

University of Michigan Sedation Scale (UMSS)

Pulse oximetry MUST BE implemented and used continuously in high-risk patients with:
-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.
-The effectiveness of the analgesia should be recorded in the Nursing Progress notes or in the appropriate clinical pathway.

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.

COMPLICATIONS

IF RESPIRATORY DEPRESSION OR OVERSEDATION IS SUSPECTED:
-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/rectal 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 attachment chart.
-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.

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