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What can we do to prevent PPOU?

In this article, Dr Jane Quinlan outlines a practical approach to reducing the risk of patients developing persistent postoperative opioid use.
Healthcare team helping patient to stand up from bed holding intravenous IV fluid drip bag after recovery surgery in hospital ward
© UCL

In this step, Dr Jane Quinlan, Consultant in Anaesthesia and Pain Medicine at Oxford University Hospitals Trust and Honorary Senior Clinical Lecturer at the University of Oxford, outlines what practical steps can be taken to reduce the risk of this complication happening to your patients.

Hospital clinicians who prescribe discharge opioids have to balance two important concepts:

Firstly, we must give the patient enough analgesia to make a good functional recovery. This will vary according to the procedure: a patient having a knee replacement will need opioids for longer than a patient having a hernia repair, for example.

It will also depend on how much opioid a patient has needed in hospital: if no opioids were needed in the 24 hours before discharge, then the patient should not be sent home with opioids.

Secondly, there is a risk of giving too much opioid on discharge so that opioids are left, unused, in the community leading to diversion, accidental overdose or continued use (PPOU).

Risk Factors for PPOU

Preoperatively Postoperatively At discharge
Opioid use Unrealistic expectations Poor education around weaning
Prescribed psychotropic drug use (benzodiazepines, antidepressants) Unidimensional pain scores Excessive amounts of discharge opioids/long duration of initial prescriptions
Female gender   Repeat prescriptions
Chronic pain   Prescription of modified-release opioids
Substance misuse    
Anxiety    
Depression    

Some of these risk factors may be modifiable, and in Week 3 you will discover how to address them practically.

Safer Principles of Postoperative Opioid Prescribing

Steps of analgesia

Acute pain gets better with healing, so we give most analgesia after surgery, then go down the analgesic steps as pain settles. This concept is referred to as the reverse pain ladder.

Strong opioids for postoperative pain must be short-acting and used only as necessary (also called pro re nata or PRN) before mobilisation or activity (see Function below).

There is no place for long-acting (modified-release) opioids in the management of acute postoperative pain.
The diagram above shows a three-step approach to weaning analgesia over time as pain decreases. In the course of normal recovery, and as pain improves, patients would be expected to ‘step down’ the ladder from left to right, stopping opioids first. Depending on the severity of postoperative pain, on discharge from hospital a patient may be started on the top step, step 3. They should be prescribed a higher potency immediate-release opioid (eg morphine or oxycodone) for a limited period, along with regular simple analgesics (paracetamol and if not contra-indicated, a non-steroidal anti-inflammatory drug – NSAID). The next step down, step 2, utilises either lower potency opioids (e.g. codeine, dihydrocodeine or tramadol) or less frequent/lower doses of a high-potency opioid (you will explore whether this makes a difference in Step 2.9). Again, these should be in combination with simple analgesics. As pain improves, opioids can be weaned off completely on step 1 with the patient continuing with paracetamol (plus NSAID) until no longer required. A larger, screen-readable version is available to download below.

Assessment

Assessing pain is important to guide analgesic prescribing.
Patients with pre-operative anxiety and depression describe higher pain scores and are more at risk of PPOU.
Despite this, it has been common in postoperative pain assessment to just use unidimensional pain scores such as the numerical pain score (“if 0 is no pain, and 10 is the worst pain imaginable, what number is your pain?”).
These scales are over-simplistic and have been a factor in the over-prescription of opioids and PPOU, as patients and clinicians chase a mythical zero (or other arbitrary target), without taking into account other factors which influence pain experience, such as anxiety. You will explore in greater detail why this is in Step 3.10.

Function

We want patients to get better, get out of bed, and get back to normal. The patient should be able to take deep breaths, sit out in a chair, do their physiotherapy, walk to the shower.
One of the goals of postoperative pain management is to allow them to do that. The functional activity score (FAS) assesses whether pain is limiting the patient’s ability to achieve a good functional recovery, such as the ability to take part in physiotherapy.

Functional Activity Scale

FAS-A No limitation: the patient is able to undertake the activity without limitation due to pain
FAS-B Mild limitation: the patient is able to undertake the activity, but experiences moderate to severe pain
FAS-C Significant limitation: the patient is unable to complete the activity due to pain or pain treatment-related adverse effects
The FAS is more useful than the numerical pain score in guiding opioid provision.

Expectations

Pain expectations are important to discuss before surgery, so that patients realise that pain is to be expected. They should understand that the goal of analgesia is to make the pain manageable and to attain functional recovery, not to be pain-free.
If your patient thinks they will have no pain after surgery, this is unrealistic. This may drive them to ask for more painkillers, and increases their risk of PPOU.

Reduction and risk management

As pain settles, it is important to reduce and stop analgesia. Opioids should be stopped first, to reduce the risk of PPOU. They should be stopped gradually, not abruptly, to avoid withdrawal.
Patients and their carers must understand the need for safe storage of opioids and to keep them away from children, due to the risk of accidental overdose. Any leftover drugs should be taken to a pharmacy for disposal, not kept at home.
When patients are discharged home, patient education is key. They need to understand the principles of safer analgesic use, and know which painkillers to take and when, and how to wean opioids.
The amount and duration of discharge opioids given are important: the risk of PPOU is higher if patients are given larger quantities or longer courses of opioids.

Best clinical practice

Identify patients pre-operatively who have a higher risk of PPOU:

  • already on long-term opioids
  • anxiety or depression
  • unrealistic expectations of a pain-free recovery

Educate patients on:

  • pain expectations
  • multimodal analgesia
  • analgesic weaning
  • safe storage
  • safe disposal

Limit discharge opioids:

  • depending on procedure
  • depending on patient use in past 24 hours
  • typically to less than a week
  • avoid repeat prescriptions of opioids after discharge
  • avoid modified-release opioids

You will explore these principles, and the supporting evidence which backs their implementation, in greater detail over the next two weeks.

© UCL
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Opioids and Surgery

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