Introduction

Acute post-operative pain is followed by persistent pain in 10–50 per cent of individuals after common operations and is severe in 2–10 per cent of cases (Kehlet, Jensen and Woolf, 2006). Unfortunately, little is known about the transition from acute to chronic pain, but the likelihood of chronic post-surgical pain (CPSP) is increased by longer duration of surgery, low (vs. high) surgical unit volume, open (vs. laparoscopic) approach and intraoperative nerve damage (Katz and Seltzer, 2009).

CPSP is defined as pain attributable to the surgical procedure present from 3 months post-operatively, with exclusion of other causes and pre-existing problems (Merskey and Bogduk, 1994).

There are known perioperative risk factors for developing chronic pain (Shipton 2014a):

Assessment

The main task is to identify patients at risk of developing CPSP preoperatively and to develop a management strategy. Similarly, it is also important to identify those at high risk to develop severe acute post-operative pain (Ip et al., 2009), as this is one of the main risk factors for CPSP (Kehlet and Rathmell, 2010).

A proportion of patients will present with preoperative chronic pain (irrespective of cause, duration and/or location) and are currently on a pain-relief regimen that may require adjusting the anaesthetic plan/procedure. Their requirements will be discussed under the substance misuse section as the management strategy is similar.

Management

For those found at risk for CPSP, proactive, perioperative management is necessary and in particular, prevention and management of acute perioperative pain risk factors for developing chronic pain (Shipton, 2014b):

Additional Considerations: Emotional Factors

• 
  

  Pain is a complex sensory and emotional experience. Study findings vary between populations and even within an individual depending on context of the pain and psychological state of the person (Villemure and Bushnell, 2002). Unfortunately, once chronic pain sets in, there is no evidence that psychological treatment is beneficial (Williams, Eccleston and Morley, 2012). For this reason, preoperative/preventative strategies focussing on stress, anxiety and fear are essential. Some important considerations are listed next:

  
  
  
  
  1. 
     

     i. Manage pre-existing psychiatric disorders: identify and address pre-existing relevant psychiatric disorders such as depression and anxiety, particularly in patients undergoing surgical procedures with higher prevalence of severe pain (Zieger et al., 2010).

     
     
  2. 
     

     ii. Manage fear: educate the patient regarding the surgical procedure and explain the nature of pain and pain management he or she could expect. Particularly look for ‘pain catastrophising’ (tendency to magnify the threat value of pain stimulus, to feel helpless in the context of pain, and to a relative inability to inhibit pain-related thoughts in anticipation of, during or following a painful encounter), which appears to be more predictive for chronic pain than anxiety in general (Theunissen et al., 2012). A single 2-hour education session combining education on surgery, pain management and elements of cognitive behavioural therapy has shown to be effective in reducing pain catastrophising (Darnall et al., 2014).

     
     
  3. 
     

     iii. Improve coping skills: optimism is a dimension of personality that is associated with better coping with acute and chronic pain experiences (Gatchel et al., 2007). Optimism cannot be taught, but it has been shown that optimistic individuals have better coping skills (Ramírez-Maestre, Esteve and López, 2012). Strategies ranging from adaptive seeking of social support and positive interactions, consistent exercise, less substance use and/or consistent utilisation of healthcare services can be learned and reinforced to improve resilience to pain (Sturgeon and Zautra, 2010).

  
  

Alcohol

Introduction

While a small number of individuals presenting to surgery may have developed addiction through recreation (usually heroin use), the majority will be individuals currently under treatment for chronic pain. In this section, we will cover the management approach regardless of reason for excessive opioid consumption, but will also make some reference to the differences in presentation.

Opioids are the mainstay therapy for alleviating moderate-to-severe pain, and one study reports that 44 per cent of patients prescribed any analgesic were prescribed an opioid (Clark, 2002).

A review indicates that the prevalence of opioid addiction is as high as 50 per cent in patients with chronic non-malignant pain and up to 8 per cent in patients with cancer pain (Højsted and Sjøgren, 2007).

Note that long-term use of opioids for non-cancer-related chronic pain may cause physical dependence, but not necessarily addiction, and the use of addiction-related terminology may lead to suboptimal pain management (Savage et al., 2003).

Finally, given the association between pre-existing preoperative pain and chronic post-operative pain, the section covering chronic pain is relevant here too.

Assessment

• 
  

  Screening

  
  
  
  
  • 
    

    The majority of patients are likely to be known for opiate use. However, if drug use is suspected, the CAGE questionnaire is applicable as a screening tool and has been adapted for drug use (Brown and Rounds, 1994).

  
  
  
  
• 
  

  History

  
  
  
  
  • 
    

    Drug history: often both patients with chronic pain and drug addiction may take several drugs that may interact with anaesthetic and analgesic drugs. Commonly used psychiatric drugs are listed in what follows, and their anaesthetic implications will be discussed in the psychiatric treatments section.

    
    
    
    
    • 
      

      Psychotropic:

      
      
      
      
      • 
        

        TCAs: amitriptyline/nortriptyline

        
        
      • 
        

        SSRIs: fluoxetine, paroxetine, sertraline, citalopram, escitalopram

        
        
      • 
        

        SNRIs: duloxetine, venlafaxine

        
        
      • 
        

        MAOIs: uncommon

      
      
      
      
    • 
      

      Anticonvulsants: gabapentin, pregabalin, valproic acid, topiramate

      
      
    • 
      

      Benzodiazepines

    
    
    
    
  • 
    

    Dependence and tolerance: dependency and tolerance are linked by the same adaptive neuro-plastic changes in neurotransmitter systems that follow repeated opioid consumption. Withdrawal symptoms are demonstrated when abrupt reduction in opioid use occurs (Jaffe, 1990). However, mechanisms underlying chronic tolerance and dependence/withdrawal are controversial and large inter-individuals differences are likely (Carroll, Angst and Clark, 2004). Similarly, while perioperative cross-tolerance amongst opioids is known to exist and may lead to increased need for analgesics (Rapp, Ready and Nessly, 1995), the completeness of this cross-tolerance is not consistent and requirements can be determined only by clinical assessment (Pasternak, 2005).

    
    

    In view of this, relevant past clinical history, such as previous periods of treatment interruptions, abstinence, detox treatments and the nature and extent of ensuing withdrawal symptoms, can provide valuable insight into the patient’s likely reaction to perioperative stress.

    
    
  • 
    

    Opioid-induced hyperalgesia: all opioids used in daily clinical practice lead to a dose-dependent reduction of the pain threshold. Remifentanil has been subject to particular investigation of opioid-induced hyperalgesia in clinical and experimental use (Angst et al., 2003).

  
  

Management

• 
  

  Perioperative opioid pain management in chronically opioid-consuming patients needs careful consideration for several reasons. (1) Opioids remain an important component of post-operative pain therapy, even in the case of substantial chronic use. (2) An adequate opioid dose needs to be maintained to prevent opioid withdrawal. (3) The transition from post-operative back to preoperative levels of opioid requirements can be a challenging process and some guidelines are listed in what follows (Carroll et al., 2004):

  
  
  
  
  • 
    

    In terms of preoperative management, it is important to:

    
    
    
    
    1. 
       

       i) Determine the following:

       
       
       
       
       • 
         

         Precise current opioid use (dose, opioid type etc.)

         
         
       • 
         

         Potential for increased post-operative pain

         
         
       • 
         

         Patient’s fears and expectations related to pain management

         
         
       • 
         

         Effective management strategies after previous procedures

         
         
       • 
         

         Post-operative management options/plan

       
       
       
       
    2. 
       

       ii) Initiation of appropriate preoperative medications:

       
       
       
       
       • 
         

         Continuation of preoperative opioid regimen on day of surgery to prevent withdrawal and falling behind on opioid requirement

         
         
       • 
         

         Consideration of paracetamol 1000 mg 1 to 2 hours before surgery

         
         
       • 
         

         Consideration of a NSAID 1 to 2 hours before surgery

       
       

    
    
    
    
  • 
    

    In terms of intraoperative management:

    
    
    
    
    1. 
       

       i) Administration of opioids to meet the following requirements:

       
       
       
       
       • 
         

         Chronic

         
         
       • 
         

         Intraoperative surgical

         
         
       • 
         

         Anticipated post-operative

         
         
       • 
         

         Titration of morphine to respiratory rate 14 to 16 if possible in spontaneously ventilating patient

       
       
       
       
    2. 
       

       ii) Administration of adjuvant medications:

       
       
       
       
       • 
         

         Ketamine 0.5 – 2 mg/kg IV bolus followed by infusion 10–45 micrograms/kg/min, adjusted to response

         
         
       • 
         

         NSAID IV (if NSAID or COX-2 not started preoperatively).

         
         
       • 
         

         Paracetamol 1000 mg IV (if not started preoperatively).

       
       
       
       
    3. 
       

       iii) Institution of appropriate regional technique:

       
       
       
       
       • 
         

         Continuous techniques preferable

         
         
       • 
         

         Wound lavage or local infiltration with local anaesthetic if other technique not possible

       
       

    
    
    
    
  • 
    

    In terms of post-operative (acute phase)

    
    
    
    
    1. 
       

       i) Titration of opioids, adjuvant medications and regional techniques to patient comfort:

       
       
       
       
       • 
         

         Expect post-operative opiate requirements to be up to two to four times the dose required in an opioid-naïve person. Remember that no individual’s requirements can be predicted with confidence.

         
         
       • 
         

         Titrate opioids aggressively to achieve adequate pain control in the post-operative care unit.

         
         
       • 
         

         Start opioid PCA: if oral route is available, start with 1.5 times the preoperative oral opioid dose and PCA for breakthrough pain. If oral route is unavailable, consider basal rate for PCA.

         
         
       • 
         

         In patients undergoing a regional technique, plan to administer at least half of the preoperative opiate requirement systemically.

         
         
       • 
         

         Continue applicable regional techniques.

         
         
       • 
         

         Continue paracetamol 1000 mg every 6 hours, and/or continue paracetamol or NSAID for several days with attention to renal function and risk of bleeding.

         
         
       • 
         

         Continue ketamine if started in the operating theatre, or institute ketamine infusion if pain proves refractory to other measures.

       
       
       
       
    2. 
       

       ii) Monitoring for over-sedation and opioid withdrawal:

       
       
       
       
       • 
         

         Chronically opioid-consuming patients are at higher risk for respiratory depression than are opioid-naïve patients and must be monitored appropriately with regular evaluation of sedation and oxygen saturation.

       
       

    
    
    
    
  • 
    

    Post-operative (transition phase)

    
    
    
    
    1. 
       

       i) Transition from regional and parenteral techniques to oral opioids and adjuvants:

       
       
       
       
       • 
         

         Use the opioid requirements during the first 24 to 48 hours to determine daily oral opioid dose.

         
         
       • 
         

         Deliver half of estimated oral requirement as a long-acting formulation.

         
         
       • 
         

         Allow PRN use of short-acting opioid every 3 hours in sufficient quantity to provide the remaining required opioid dose.

         
         
       • 
         

         Consider continuing paracetamol, NSAID or COX-2 inhibitor during transition phase.

       
       
       
       
    2. 
       

       ii) Plan taper from post-operative opioid doses towards preoperative doses and discuss with patient or care provider. Determine need for specialty follow-up if regimen is particularly complex.

    
    

  
  

Introduction

One in four British adults experiences at least one diagnosable mental health problem in any one year, which will be mostly mild and self-limited. Serious mental conditions will be present in a small proportion who will have a mortality rate two to three times higher than the general population (O’Brien et al., 2001). About 60 per cent of this mortality is due to physical health problems (Parks et al., 2006), which means that patients with severe mental health problems frequently have serious physical health problems, often unrecognised or poorly treated. These findings suggest their survival from essential medical procedures will be significantly below the general population (Kisely et al., 2007).

Assessment

Apart from the general preoperative assessment, the following issues need to be considered when assessing a patient with mental health problems:

1. 
   

   a) Patients with mental health disorders can be reluctant historians. Sufficient time should be allowed for this assessment and efforts to engage and empathise with the patient will be rewarded with more accurate information.

   
   
2. 
   

   b) Whenever possible, a carer (usually a relative) should be present for emotional support and to provide collateral information such as medication history and compliance.

   
   
3. 
   

   c) As usual, when explaining both the procedure and risks, medical jargon should be avoided and the patient’s understanding should be frequently checked.

   
   
4. 
   

   d) If there is doubt whether the patient has capacity to consent or refuse the surgical procedure, he or she should have his or her capacity assessed. Capacity assessment is ‘task-specific’, and one should not have a ‘blanket approach’. The BMA has a ‘Capacity Toolkit’ that is easy to use (http://bma.org.uk/practical-support-at-work/ethics/mental-capacity-tool-kit) with further details in relation to the Mental Capacity Act (Act, 2005). In general, if a patient has capacity, he or she should be able to:

   
   
   
   
   1. 
      

      i. understand the information relevant to the decision;

      
      
   2. 
      

      ii. retain the information relevant to the decision;

      
      
   3. 
      

      iii. use or weigh the information;

      
      
   4. 
      

      iv. communicate the decision, by any means.

   
   

Important History Findings

Physical Exam Findings

Psychiatry is almost devoid of physical signs of mental health disorders, but scars from self-inflicted cuts on limbs or abdomen in adolescents should prompt further discussion/investigation.

This is a marker of deliberate self-harm, which may be found in patients with a history of depression (Muehlenkamp and Gutierrez, 2004). Further exploration of past and present depressive symptoms is warranted.

Additional Considerations: Chronic Pain

• 
  

  Mental health disorders such as depression and anxiety are a risk factor for development of chronic post-surgical pain (Shipton, 2014a), and this association is covered in the section on chronic pain.

Recommendations

The European Society of Anaesthesiology makes the following recommendations in relation to psychotropics in the preoperative evaluation of the adult patient undergoing non-cardiac surgery (De Hert et al., 2011):

Patients chronically treated with TCAs should have an ECG to look for long QT syndrome and undergo cardiac evaluation prior to anaesthesia:

1. 
   

   i) Antidepressant treatment for chronically depressed patients should not be discontinued prior to anaesthesia.

   
   
2. 
   

   ii) Discontinuation of SSRI treatment perioperatively is not recommended.

   
   
3. 
   

   iii) Irreversible MAOIs should be discontinued at least 2 weeks prior to anaesthesia. To avoid relapse of underlying disease, medication should be changed to reversible MAOIs.

   
   
4. 
   

   iv) The incidence of post-operative confusion is significantly higher in schizophrenic patients if medication was discontinued prior to surgery. Thus, antipsychotic medication should be continued in patients with chronic schizophrenia perioperatively.

   
   
5. 
   

   v) Lithium administration should be discontinued 72 hours prior to surgery. It can be restarted if the patient has normal ranges of electrolytes, is haemodynamically stable and can eat and drink. Blood levels of lithium should be controlled within 1 week.

Finally, for cases where multiple psychotropic drugs are used, a tailored multidisciplinary case-by-case management plan that includes a psychiatrist and pharmacist is recommended.