Acute post-operative pain is a major risk factor for post-operative chronic pain. Prevention of chronic pain involves identifying those with pre-existing risk factors and actively and effectively treating post-operative pain, as well as addressing its emotional aspects.
Drugs of abuse that cause physical dependence such as alcohol and opiates may have a significant and often unpredictable impact on pharmacological aspects of perioperative management. Actively managing pain control along with regular monitoring and treatment of withdrawal symptoms should be a priority perioperatively.
Psychiatric patients are at significantly higher risk of physical health problems than the general population and of below-average survival rates from surgical procedures. Factors that improve outcomes include psychoeducation about the surgery, actively screening for and treating depression and having a multidisciplinary approach to decide on perioperative management of psychoactive drugs.
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):
Demographic perioperative factors associated with development chronic pain are younger age, female gender, genetic disposition, anxiety and fear, preoperative pain distant from the surgical site and/or preoperative pain at the surgical site.
Intraoperative risk factors include surgical site (for example thoracotomy, sternotomy, limb amputation), open surgery (rather than minimally invasive), duration of the surgery and surgery related nerve damage due to compression, stretching and ischaemia.
Post-operative risk factors include unrelieved and severe pain in the immediate post-operative period, high post-operative use of analgesics and surgery performed in a previously injured area.
Radiation therapy and chemotherapy; Repeated surgery in the same area;
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.
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):
Perioperative prevention and management includes individualised education of patient and clinical staff (about procedure and intended pain management); supplying relevant patient information; addressing patient attitudes and concerns; identifying operative procedures that cause severe pain; aggressively optimising analgesia in acute injury and preoperative phase and extending into postoperative period; using standardised pain evaluation and treatment protocols to identify patients with modifiable risk factors for development of acute persistent and ultimately chronic pain to inform follow-up and manage after discharge and screening and providing perioperative psychological pain-management interventions where relevant.
Intraoperative prevention and management includes modifying known surgical risk factors; using the least painful surgical approach with acceptable exposure; preventing nerve and tissue damage; providing protective multimodal opioid-sparing analgesic pharmacotherapy; adding afferent neural blockade such as epidural or paravertebral analgesia where appropriate, using local anaesthesia at incision sites and using a procedure-specific analgesic regimen (from the procedure specific postoperative pain management (PROSPECT) group wherever possible).
Postoperative prevention and management include measuring pain levels at rest and with movement; aggressively optimising analgesia with protective multimodal opioid-sparing analgesic pharmacotherapy (consider use of gabapentin) and aiming at keeping pain levels <5/10 on days 1–5 postoperatively; using a multidisciplinary enhanced postoperative recovery programme; using evidence-based adjustments to the use of nasogastric tubes, drains, and urinary catheters, preoperative bowel preparation, and early initiation of oral feeding and mobilisation; performing a bedside neurological examination if neuropathic pain is suspected; continuing analgesia well into the postoperative period and devising individualised discharge analgesic packages and home follow-up.
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:
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).
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).
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).
Risk factors for developing chronic pain include preoperative, intraoperative and post-operative factors.
Pain is a complex sensory and emotional experience. Addressing perioperative emotional factors such as stress, anxiety and fear is essential to reduce the chances of the development of chronic pain.
Like many other chronic conditions, such as diabetes, cardiovascular disease and asthma, addiction is a multidimensional disease where substance misuse is part of a complex pattern of behaviour function of psychological, genetic and social factors (McLellan et al., 2000).
Note that substance misuse falls under the mental health disorders section in the 10th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD – 10), a medical classification list by the World Health Organization (WHO), and as such the complex psychosocial factors discussed in the psychiatric disorders section should apply here.
From a perioperative point of view, the biological and pharmacological aspect of substance misuse will have the most significant impact on management. For this reason, we will discuss in more detail the drugs commonly associated with physical dependence and withdrawal syndromes, namely alcohol and opioids.
There is no linear association between the amount of substance being used and the perioperative requirements and risks. Therefore, the management plan, no matter how good, is only as good as its implementation with frequent reviewing by a multidisciplinary team.
Alcohol abuse is a serious public health concern, contributing to 4 per cent of the burden of disease and 3.2 per cent of all deaths globally (World Health Organization, 2002). It resulted in premature mortality (in European men between 15 and 64) of 1 in each 7 deaths in 2004. For women of the same age category, 1 in 13 deaths were caused by alcohol.
The incidence of hazardous drinking is 7–49 per cent for general surgical populations undergoing elective procedures and 14–38 per cent for emergency procedures in the Western world (Tønnesen, 2002). A recent meta-analysis found that preoperative alcohol consumption was associated with an increased risk of post-operative mortality, risk of general post-operative morbidity, generalised infections, wound complications, pulmonary complications, prolonged stay at the hospital and admission to an intensive care unit. However, the strength of this association is still unclear due to methodological issues of this study (Tønnesen, 2002).
Chronic alcoholics can be difficult to identify at the preoperative clinic. One study looking at preoperative evaluation for surgery of the upper digestive tract reported that only 16 per cent of chronic alcoholics were detected by a single preoperative visit (Martin et al., 2002). For these reasons, it is essential to accurately and reliably identify those whose consumption of alcohol is likely to lead to post-operative complications.
The CAGE questionnaire (Ewing, 1984) is a well-established screening tool for the detection of alcohol-use disorders in high-risk patients. The questionnaire includes four questions: ‘C’ (cut down): Have you felt you ought to cut down your drinking or drug use?; ‘A’ (annoyed): Have people annoyed you by criticising your drinking or drug use?; ‘G’ (guilty): Have you felt bad or guilty about your drinking or drug use?; ‘E’ (eye-opener): Have you ever had a drink or used drugs first thing in the morning to steady your nerves or to get rid of a hangover (eye-opener)? The test is considered positive once the sum score yields more than two points, and a more comprehensive drug history should be obtained.
Once the patient at risk is identified, a tailored perioperative management plan is necessary. The extent and nature of preoperative management is a clinical decision that can be complex, and a blanket approach is not advisable. For instance, some patients may have severe addiction and the balance of the pros and cons of elective surgery must be considered. For less severe cases, there is evidence that 1 month abstinence prior to the surgery has a positive impact on various perioperative parameters (Tønnesen, 2002).
In cases where elective surgery is warranted, additional substitution of thiamine (200 mg given parenterally for 3–5 days) is indicated to prevent Wernicke’s encephalopathy. Perioperatively, the main aim is to prevent the onset of alcohol withdrawal syndrome or to attenuate its severity, and transition from prevention to treatment is continuous (Spies et al., 1995).
It is recommended that perioperative management of patients with alcohol disorder having elective surgery should include (Kork, Neumann and Spies, 2010):
Morphine 15 mg/kg per hour initiated before induction of anaesthesia and maintained until day 3 after surgery or alternatively, if the patient agrees, post-operatively 0.5 g/kg per day ethanol instead of morphine;
As premedication: (i) long-acting benzodiazepine (such as diazepam) the evening before surgery, (ii) short-acting benzodiazepine (such as midazolam) the morning of surgery. If not adequately pre-medicated: midazolam (0.5–5 mg IV titrated).
After induction clondine (0.5 mg/kg per h), haloperidol (up to 3.5 mg per 24 h) and ketamine 0.5 mg/kg.
Occasionally, despite thorough planning, the patient may present with alcohol withdrawal symptoms and it is recommended that patients are monitored using the revised clinical institute withdrawal assessment for alcohol scale (CIWA-Ar) at least twice a day (Sullivan et al., 1989). This excellent scale rates the severity of 10 indicators/symptoms of alcohol withdrawal. The sum of scores will indicate whether alcohol withdrawal syndrome is mild, moderate, moderately severe or severe. If necessary, treatment should be with oral benzodiazepinics such as chlordiazepoxide. There are many different regimens, but regular doses every 4–6 hours with symptom-triggered extra doses (CIWA-Ar score of 8 or greater) have shown to decrease both treatment duration and the amount of benzodiazepine used, and is as efficacious as standard fixed-schedule therapy for alcohol withdrawal (Saitz et al., 1994).
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.
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).
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.
SSRIs: fluoxetine, paroxetine, sertraline, citalopram, escitalopram
SNRIs: duloxetine, venlafaxine
Anticonvulsants: gabapentin, pregabalin, valproic acid, topiramate
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).
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:
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
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
In terms of intraoperative management:
i) Administration of opioids to meet the following requirements:
Titration of morphine to respiratory rate 14 to 16 if possible in spontaneously ventilating patient
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).
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)
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.
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)
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.
Once the patient at risk is identified, a tailored perioperative management plan is necessary. The extent and nature of preoperative management is a clinical decision that can be complex, and a blanket approach is not advisable.
In cases where elective surgery is warranted, the aim of perioperative management will be to prevent the onset of alcohol withdrawal syndrome or to attenuate its severity, and may include the use of drugs such as morphine, benzodiazepinics, clonidine, haloperidol and ketamine.
In the presence of withdrawal symptoms, the CIWA-Ar can be used to rate symptoms’ severity to guide treatment with oral benzodiazepinics such as chlordiazepoxide.
Preoperatively, opioid addiction is usually more frequently seen in the context of chronic pain treatment rather than recreational use.
Physical dependence can occur in the absence of addiction to opioids when treating severe non-malignant pain, and should not prevent effective perioperative analgesia.
Mechanisms underlying chronic tolerance and dependence/withdrawal are controversial, and large inter-individual differences are likely. Therefore, eliciting 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.
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.
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).
Apart from the general preoperative assessment, the following issues need to be considered when assessing a patient with mental health problems:
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.
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.
c) As usual, when explaining both the procedure and risks, medical jargon should be avoided and the patient’s understanding should be frequently checked.
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 (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:
i. understand the information relevant to the decision;
ii. retain the information relevant to the decision;
iii. use or weigh the information;
iv. communicate the decision, by any means.
Important History Findings
It is important to obtain a detailed account of regular, occasionally prescribed, as well as over-the-counter medication. During surgery, psychotropic drugs may be hazardous due to direct effects and/or interactions. On the other hand, if ceased prior to surgery, some drugs have the propensity to cause withdrawal symptoms. Similarly, withdrawing a psychoactive medication from a patient known to quickly relapse if ceased is a risk that may outweigh the perceived benefits of withholding these perioperatively.
Ultimately, the decision whether to continue, reduce the dose or cease a psychoactive drug perioperatively should be on a case-by-case basis, made by a multidisciplinary team and taking the following factors into consideration:
Severity/complexity of psychiatric disorder
History of frequent relapses
Risks to self and others in case of relapse
Insight and engagement with care plan
Nature of surgical procedure
Nature of psychoactive drug(s) in question
Propensity to cause withdraw symptoms
Screening for Depression
Depression is a very common disorder, with one in five people becoming depressed at some point in their lives (Self, Thomas and Randall, 2012). Moreover, depression is associated with chronic illness, causing maladaptive effects such as amplification of somatic symptoms, increase in health-adverse behaviours, lack of adherence to medical regimens and consequent direct maladaptive physiologic effects modulated by the autonomic nervous system with hypothalamus and immunologic effects (Katon, 1996). In fact, a systematic review revealed that 19 out of 47 surgical outcomes were predicted by a mood factor (Rosenberger, 2006). Therefore, promptly identifying depression and rating its severity should be a priority, particularly in the elderly (Givens, Sanft, and Marcantonio, 2008). The Patient Health Questionnaire PHQ-9 (Kroenke, Spitzer and Williams, 2001) is a free-of-charge scoring system comprising nine questions to diagnose and rate severity of depression. If depression is diagnosed, the following steps are suggested:
An open discussion with the patient (and or carers) about the risks the disease poses for recovery
A multidisciplinary team discussion (surgeon, psychiatrist, anaesthetist) around the need of treatment and the timing of the surgery, as well as pre- and post-operative management
Consider arranging an additional education session. There is evidence that improving and addressing surgery-related expectations (Iversen et al., 1998) and the quality of procedural as well as post-operative management information (Johnston and Vögele, 1993) may improve early surgical outcomes (Mavros et al., 2011). Addressing the gaps between information given and expectations can mediate a post-operative depressive state (Stark et al. 2014).
Neurodevelopmental Disorders and Intellectual Disabilities
Patients with intellectual disability and/or neurodevelopmental disorders such as autism have a high lifetime rate of psychiatric disorders (Croen et al., 2015; Salazar et al., 2015). In addition, a recent study has shown that autistic patients are known to have a markedly increased premature mortality in all analysed diagnostic categories, with mortality and patterns for cause-specific mortality partly moderated by gender and general intellectual ability (Hirvikoski et al., 2015). Therefore, patients with such disorders need careful support when facing surgical procedures, with careful planning of post-operative care to reduce distress and subsequent use of sedatives post-operatively. Strategies that will help to reduce stress perioperatively include:
Determining their personal preferences, which will range from special areas of interest (for topics of conversation) to sensory preferences (food, smell, touch, visual and auditory stimuli). This can help to reduce anxiety and foster cooperation.
Use of visual information cards to illustrate what will happen on the day of surgery (www.easyhealth.org.uk/sites/default/files/What%20happens%20when%20you%20go%20into%20hospital.pdf).
Introducing the patient to a member of the surgical team that will be present on the day of procedure.
Physical Exam Findings
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.
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:
i) Antidepressant treatment for chronically depressed patients should not be discontinued prior to anaesthesia.
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.
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.
Patients with severe mental health problems frequently have serious physical health problems, often unrecognised or poorly treated, and their survival from essential medical procedures will be significantly below the general population.
The preoperative assessment of patients with known mental health problems should carefully determine capacity to consent and obtain good-quality clinical information and a detailed drug history.
The decision whether to continue, reduce the dose or cease a psychoactive drug perioperatively should be on a case-by-case basis, preferably by a multidisciplinary team, and consider the recommendations from the European Society of Anaesthesiology.
Screening for depression is important as it is a very common disorder and many surgical outcomes are predicted by a mood factor.
Patients with intellectual disability and or neurodevelopmental disorders such as autism have a markedly increased premature mortality and need careful support when facing surgical procedures.