Download patient controlled analgesia

Pain facts 7
Dr. S. Parthasarathy
MD., DA., DNB, MD (Acu), Dip. Diab.
DCA, Dip. Software statistics
PhD (physio)
Mahatma Gandhi medical college and
research institute , puducherry – India
Patient controlled analgesia
• The patient controls his own analgesia
• the use of a sophisticated microprocessorcontrolled infusion pump that delivers
a preprogrammed dose of opioid when the
patient pushes a demand button
Patient controlled analgesia
• Any analgesic given by any route of delivery (i.e.,
oral, subcutaneous, epidural, peripheral nerve
catheter) can be considered PCA if administered
on immediate patient demand in sufficient
quantities.
• But routine is IV opioids
Background
• The traditional approach of IM opioids
given pro re nata (prn) results in at least
50% of patients experiencing inadequate
pain relief after surgery.
• Sechzer - the true pioneer of PCA evaluated
the analgesic response to small IV doses of
opioid given on patient demand by a nurse
in 1968 and then by machine in 1971
We don’t want action after distress
• Pain
nurse
dilutes prepares drug
P
C
A
Analgesia
Blood
conc.
absor
IM
MEAC
Indications
•
•
•
•
•
•
•
Acute post op pain
Trauma
Cancer
Labour
Burns
Sickle cell crisis
Sedation
Advantages
• Better analgesia with same sedation
• Better pulmonary results and less
complications
• Length of hospital stay
• POCD is less
• Patient satisfaction
Relative contraindications
•
•
•
•
•
Sepsis
Fluid electrolyte disturbance
Hepatic or renal disease ( severe disease )
Sleep apnoea
Severe COPD
PCA system
•
•
•
•
•
•
Programmable electronic devices
Flexibility ,
Display and memory, cost
Disposable fixed programme devices
Nonweight , hydrostatic pressure based
No alarms, rudimentary but cheap
How to use
• Methods
•
•
•
•
Demand dose ,
DD + basal infusion ,
DD + tail
Adjustable infusions
Variables
•
•
•
•
•
Loading dose
Demand dose
Lock out interval
Basal infusion
1 or 4 hourly maximum
• Variables + drug = prescription
Loading dose
• We should understand that PCA is a
maintenance therapy
• It needs loading dose.
Loading dose
• HIGH LOADING DOSE
• OPIOID BASED ANAESTHESIA
• Correlated with less analgesic requirements
• Morphine – 3 -5 fentanyl 50 mic
• Pethidine – 25 tramadol 100
Basal infusion
• Less fluctuation ,increased pt. satisfaction
• Sleep more medication
• Per hour doses
• Morphine – 1 fentanyl 10 mic
• Pethidine – 25 tramadol 12
Demand dose
• The amount of drug injected as soon as the
patient presses the button
• Burp or tweek sound
• dose is too small, they stop making demands
• become frustrated with PCA, resulting in
poor pain relief
• Upto 5-6 doses / hour
Demand dose
• Demand dose is too large, plasma drug
concentration may eventually reach toxic
levels- side effects ensue
• Optimal dose
• Morphine - 1 mg
• Pethidine – 10 mg
• Fentanyl – 10 mic
Lock out interval
• Patient cant go on to press 10 times in half
hour – get toxic doses
• The time delay before the patient cannot go
to the next dose
• Onset of action of the drug
• Fentanyl and morphine
• Relative onset and duration ??
Classical times
• Morphine – 8 min
• Pethidine – 8 min
• Fentanyl - 6 minutes
• Short dose and lock out
• Large dose and lock out
• Fentanyl -- ?
Lock out ??
• Brain to blood
• Blood to brain
• Redistribution
Demand dose or lock out
• Attempts
• Sound
• May deliver or not
• Adjusted infusion
Nothing like this
• One size fits all
• Set and forget
• The doses are only approximate
Patient weight prevents toxicity but efficacy ?
Total dose
• 1 hour
• 4 hours
Assumptions
• Side effects are produced at higher brain
concentrations than the analgesic effect
• Pain intensities are rarely constant
• Pain relief is ideal in MEAC only
Ideal opioid
•
•
•
•
Rapid onset
Medium duration
Less side effects
No ceiling to analgesia
• Morphine -- pethidine – fentanyl
Morphine - ?
•
•
•
•
Renal insuffiency
Bilirubin
Preeclampsia
Smooth muscle spasm
Pethidine
• Seizures
• Sickle cell crisis nor meperidine increased
• Papillary necrosis in renal dysfunction
Fentanyl
• Ideal for renal and hepatic dysfunction
cases
• But short duration should be in mind
• Other drugs – hydromorphone, pentazocine
and buprenorphine are used
Monitoring
•
•
•
•
Staff
ABG
Respiration
Sedation score
• But pulse oximetry is accepted as the
monitor for PCA
Side effects
• Operator error
• Patient error
• Equipment malfunction
Side effects of opioids
• Nausea and vomiting
• No difference
• 30 % Vs 25% - PCA Vs IM
• Use of anti emetics – similar
•
Respiratory depression
• PCA is more – wrong
• Lot of studies – 0.5 – 0.9 % Vs
• Old age , COPD, equipment failure,
concomitant opioid admin by other routes,
wrong doses
Colonic pseudoobstruction
•
•
•
•
Abd, distension
Nausea
Vomiting,
Flatus
• Yes but 6/154 in a study of PCA -- not
threatening
Others
• Sedation - 20 %
• Dizziness - 13 %
• Pruritus - 20 %
• In a study with PCA with hydromorphone
PCA adjuncts
•
•
•
•
•
Promethazine –
Droperidol
Metoclopramide
TDS scopolomine
Naloxone
•
•
•
•
NSAIDs
Clonidine
Paracetomol
Nerve blocks
Other methods - PCEA
loading – basal – demand- lock out
• Morph. 2
0.5
0.2
30
• Peth.
30
• Fentanyl 50
10
30
10
20
10
15
Subcutaneous (clysis)
• 0.2 mg Loading with 0.2 mg demand SC 15
min. lock out of hydromorphone
• Obesity
• Edema
• Vasculitis
• But if no proper IV access – OK
Rare routes
•
•
•
•
•
•
Intramuscular PCA
Paediatric PCA
Intraspinal PCA
Ventricular implantable PCA
Oral PCA
PCA with ketoroloc, midazolam has been
done
Mr. X
•
•
•
•
Mr X bought a scooter
He did not know driving
He was struggling
One friend came near to say don’t worry, it
will normalize in three months
• Mr. X put the scooter into the shed to try
it after three months
To understand PCA
• USE it
• Make it available in your institutes
Thank you all