Preparing patients for surgery: Perioperative care and general practice

Heart failure, coronary and valvular heart disease

Cardiovascular complications are a significant cause of perioperative morbidity and mortality (Smilowitz et al., 2018). Approximately 45% of surgical patients over 45 years old have multiple cardiovascular risk factors, and major adverse cardiovascular events occur in 3% of patients following non-cardiac surgery. Procedures in some surgical specialties, such as vascular surgery, carry an elevated risk of cardiovascular complications compared with others (Smilowitz and Berger, 2020).

A focused history and examination can detect clinically significant, or undiagnosed coronary or valvular disease or congestive cardiac failure and prompt early investigation, in line with usual practice. Primary care targets aim to modify cardiovascular risk factors through tight control of hypertension, hyperlipidaemia and diabetes, optimisation of angina management and support of lifestyle changes including increasing aerobic exercise and smoking cessation.

Prior to surgery, symptoms should be stable. It may be appropriate to expedite cardiology referrals when symptoms significantly limit exercise tolerance. Poor mobility may make it difficult to quantify exercise tolerance and, in such circumstances, referral for further investigation is appropriate, with, for example, a transthoracic echocardiogram to allow objective evaluation of cardiac function. Details of any pacemakers or implanted defibrillators should be included in referral letters to plan for device management during surgery. All devices require a check within 1 year of a planned procedure.

Atrial fibrillation

Atrial fibrillation (AF) is the most commonly reported perioperative arrhythmia, affecting 10% of patients following non-cardiac surgery. AF is a major risk factor for perioperative thromboembolic events (e.g. stroke and ischaemic bowel), cardiac failure and death (Lin et al., 2019).

Rate control is the primary objective for optimising patients with AF prior to surgery, as cardiac output can fall dramatically with tachycardia. Evidence supporting a specific preoperative heart rate target is limited, but typically a heart rate of 60 to 80 beats per minute at rest is considered optimal. Heart rates exceeding 90 beats per minute require further medical management in line with usual practice. Precipitants of AF, such as electrolyte disturbance and deranged thyroid function, are best corrected before patients are reviewed in preoperative assessment clinics (POAC) to avoid deferral of surgery.

Patients should expect to receive clear instructions from POACs about anticoagulant and antiplatelet medications in the immediate perioperative period. However, it may be of interest that in most circumstances, anticoagulants are temporarily suspended without bridging therapy, due to the risk of uncontrollable surgical bleeding.

Hypertension

Isolated uncontrolled hypertension has historically been a common cause for last-minute deferrals of elective surgery, due to a perceived risk of adverse cardiovascular events and haemodynamic instability. Nowadays, a more pragmatic approach considers all of a patient’s risk factors for perioperative cardiovascular complications, thus reducing the number of same-day cancellations. Reducing the cardiovascular and cerebrovascular risks associated with uncontrolled hypertension, using lifestyle modification strategies and antihypertensive medications, is the focus of perioperative optimisation (Tait and Howell, 2021).

Perioperative blood pressure targets are different from non-perioperative NICE guidance and recognise that targeting low preoperative blood pressures does not modify the risk associated with surgery and can cause unnecessary delays to elective surgery (Fig. 1). Patients with blood pressures under 160/100 mmHg can be referred for elective surgery. Waiting times for surgery can be substantially longer than the time for antihypertensive therapy to take effect and referral for surgery need not be delayed when treating hypertension. Including patients’ average blood pressure readings in referral letters may avoid the postponement of surgery from otherwise anomalous high measurements in the POAC (Hartle et al., 2016). Secondary hypertension, accounting for 5–15% of hypertensive patients, must be considered in those less than 40 years of age, or with extreme and acute hypertension resistant to usual management.

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Figure 1.

Blood pressure recommendations for patients before referral for elective surgery.

Chronic respiratory disease

Surgery and anaesthesia can dramatically compromise respiratory function in patients with a chronic respiratory disease. The risk of a patient with asthma developing intraoperative bronchospasm is considerably higher if they have had poor control in the past 30 days, and poor preoperative respiratory function in chronic obstructive pulmonary disease (COPD) is a concerning predictor of respiratory complications requiring postoperative intensive care support (Ntima and Lumb, 2019). For patients with severe respiratory disease, general anaesthesia can precipitate acute decompensation.

Pulmonary function tests performed in primary care inform the management of poorly-controlled or brittle asthma and COPD, and are especially useful when referring patients following repeated courses of steroids or antibiotics in the past 6 months (Ntima and Lumb, 2019). Referral letters should detail the patient’s exercise tolerance and functional status, so that specialist preoperative investigations can be expedited. Subjective descriptions of functional status are helpful, and so are simple objective and validated functional screening tools, for example the Duke Activity Status Index. The goal of usual management should be symptom stability and escalation of inhaler therapies in accordance with national guidelines (British Thoracic Society and Scottish Intercollegiate Guidelines Network, 2019). Smoking cessation support and vaccination are part of routine care. Referral for surgery is a powerful opportunity to motivate and re-educate patients about positive lifestyle choices; teachable moments.

SARS-CoV-2 is topical and worthy of discussion here. Non-urgent surgery is currently delayed until 7 weeks after a positive test and resolution of the symptoms of acute infection. Earlier surgery is associated with postoperative complications and death. This guidance also applies to asymptomatic or mildly symptomatic omicron SARS-CoV-2 as assumptions of reduced perioperative risk in this group are unfounded. Recommendations may be revised as further data emerge. Physical deconditioning and ‘long COVID’ pose unique perioperative challenges. Services managing patients suffering severely after SARS-CoV-2 infection should be utilised when available (El-Boghdadly et al., 2022).

Anaemia

Anaemia significantly impairs physiological reserve following surgery, due to decreased oxygen-carrying capacity. Anaemia increases the need for blood transfusions and the risk of surgical complications. Elective surgery is typically deferred until anaemia is corrected and the threshold for treating anaemia is lower in the elective surgical population than in standard practice. The prevalence of preoperative anaemia is approximately 35%, and a haemoglobin of 130 g/L or higher is recommended for both men and women (Muñoz et al., 2017). Targets before emergency and urgent surgery are necessarily more lenient.

Investigation in primary care can prevent delays to surgery. Serum ferritin level <30 µg/L most accurately identifies absolute iron deficiency. Serum ferritin level 30–100 µg/L and transferrin saturation <20% suggests anaemia of chronic disease with iron deficiency. Low serum vitamin B12 and folate should be excluded and managed in accordance with usual practice. If the cause of anaemia is not known, sinister causes should be considered and non-urgent surgery delayed. Anaemia associated with advanced chronic kidney disease (grade 4 and 5) poses a unique challenge and requires early specialist nephrology input, with lower therapeutic targets due to the increased risk of thrombosis with ‘normal’ haemoglobin levels.

Oral iron replacement is convenient and safe when treating iron deficiency anaemia and, when indicated, should commence in primary care. Non-anaemic patients with absolute iron deficiency may benefit from preoperative iron replacement therapy to improve recovery from surgical blood loss. When the interval to surgery is at least 6 to 8 weeks, nutritional advice and either daily (equivalent 40–60 mg) or alternate-day (equivalent 80–100 mg) oral iron replacement is appropriate. Low daily doses, alternate-day dosing or liquid preparations are better tolerated, without impacting efficacy (Auerbach, 2021). GPs managing anaemia should ensure that serum haemoglobin is checked at least 4 weeks before surgery to ensure that treatment has been effective. Intravenous (IV) iron is a safer and more cost-effective solution to refractory anaemia, compared with perioperative blood transfusion. It is also useful when oral iron is poorly tolerated or when the interval to surgery is less than 4 weeks. Specialist referrals may be indicated when community IV iron services are not available, but treatment should not be delayed until POAC assessment (Muñoz et al., 2017).

Obesity

Obesity is associated with a number of unique perioperative challenges, from logistical issues in the theatre environment to difficult airway management and poor operating conditions. The most concerning problems relate to the impact of anaesthesia and surgery on altered patient physiology with increased BMI and obesity-related comorbidities. Complications are primarily attributable to postoperative respiratory failure and hypercoagulability causing thromboembolic events. Obesity may not only precipitate respiratory disease, such as sleep-disordered breathing, but also exacerbate obstructive respiratory diseases.

Management of obesity in primary care requires a holistic approach to address the complex biopsychosocial aetiology, and it is appropriate in this article to describe some specific, relevant goals for treatment. Referral for surgery can motivate obese patients to make radical lifestyle changes that significantly reduce their risk of perioperative complications. A 5–10% weight reduction target can significantly reduce obesity-related complications and improve operating conditions for the surgeon. Obese patients with ‘asthma’ and a poor response to bronchodilators may recover with weight loss if the wheeze is attributable to airway collapse (Nightingale et al., 2015). Sleep-disordered breathing, a spectrum from obstructive sleep apnoea to obesity hypoventilation syndrome, more than doubles the risk of postoperative respiratory failure, cardiac events and unplanned intensive care admissions. Although not yet widely used in primary care, we recommend GPs use the STOP-BANG questionnaire (Table 1) to screen for sleep-disordered breathing and prompt initiation of weight loss programmes or specialist referral for continuous positive airway pressure devices (Carron et al., 2020).

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Table 1.

STOP-BANG screening questionnaire for sleep-disordered breathing. 1 point is given for each positive feature, a scores of 5 or greater suggest a significant risk of sleep-disordered breathing.

Snoring	Do you snore loudly (loud enough to be heard through a closed door)?
Tired	Do you often feel tired, fatigued, or sleepy during daytime?
Observed	Has anyone observed you stop breathing during your sleep?
Blood pressure	Do you have, or are you being treated for, high blood pressure?
BMI	BMI over 35 kg/m2
Age	Age over 50 years
Neck circumference	Neck circumference greater than 40 cm?
Gender	Male

Reproduced from Chung F, Yegneswaran B, Liao P, et al. (2008). STOP questionnaire: a tool to screen patients for obstructive sleep apnea. Anesthesiology, 108(5): 812–821, with permission from Wolters Kluwer Health, Inc.

Diabetes mellitus

Poorly controlled type 1 and type 2 diabetes mellitus is associated with micro- and macrovascular pathology, immunosuppression and complex polypharmacy. Patients with diabetes are more likely to require surgery and have up to 50% higher perioperative mortality rates than those without diabetes. For example, diabetes mellitus carries an increased incidence of postoperative respiratory and urinary tract infection, surgical site infections, myocardial infarction and acute kidney injuries that prolong hospital admissions (Barker et al., 2015).

Poorly controlled diabetes mellitus can delay elective surgery by between 3 and 12 months while multiple organ impairments are addressed. Optimisation of glycaemic management in primary care ahead of surgery aims for an HbA1c of less than 69 mmol/mol within the 3 months before referral, if safe and practical. Diabetes-related comorbidities should be addressed, specifically screening for cardiovascular and renal disease. This may involve GPs initiating antihypertensive medication, statins and antiplatelets in accordance with national guidelines, and referral for specialist diabetes support. GPs should counsel their patients on the benefits of making healthy lifestyle changes that can improve surgical outcomes. Referral for surgery can motivate engagement with community-based weight loss programmes, smoking cessation and prescribed physical exercise services, when available (Centre for Perioperative Care, 2021).

It is important that all diabetes-related comorbidities are communicated in referral letters, including recent blood pressure measurements and BMI, relevant investigations such as renal function and HbA1c, and a comprehensive list of the patient’s current medications and medical devices (e.g. insulin pumps).

Smoking and alcohol misuse

Smokers are 38% more likely to die and twice as likely to suffer with major morbidity following surgery, when compared with non-smokers. The commonest causes are cardiorespiratory complications, infections and poor wound healing. These can lead to longer hospital stays, more days spent in intensive care and more emergency readmissions to hospital (Carrick et al., 2019). Excess alcohol intake may also significantly impact surgical outcomes. Referrals from primary care should highlight smoking and excessive alcohol intake.

GPs and community-based nurses already provide the majority of smoking cessation and alcohol moderation support, but the prospect of surgery can motivate patients to better engage with these services. Intensive preoperative smoking cessation requires abstinence for 3 to 8 weeks prior to surgery. Trial data shows 10-fold higher quit rates among smokers recruited to programmes that combine behavioural support with pharmacotherapy, when compared with patients provided with inconsistent smoking cessation advice from nurses, surgeons and anaesthetists (Thomsen et al., 2014). Any reduction is likely to benefit patients and the longer the period of abstinence the better.

Frailty

The risk of frailty increases substantially with age and affects 300 000 older people who undergo elective and emergency surgery in the UK each year. Frail patients with a Clinical Frailty Scale (CFS) score ≥5 suffer from a loss of physiological reserve, global physical decline and deconditioning, making them more vulnerable to complications. 70% of patients living with frailty are also multimorbid and highly vulnerable not only to the associated perioperative complications, but also to delirium, falls, hospital-acquired deconditioning and complex discharge issues (Centre for Perioperative Care and British Geriatric Society, 2021).

It is important to emphasise that living with frailty should not affect a patient’s right to access appropriate surgical treatment. GPs, as advocates for patients, their wishes and values, can discuss aims and expectations for physical, mental and functional recovery following surgery.

Optimising frail patients for surgery is very challenging, and with increasing severity may be beyond the capabilities of primary care providers. The Centre for Perioperative Care and the British Geriatric Society jointly published comprehensive guidelines for the perioperative management of frail patients, with specific reference to the role of primary care (Fig. 2). As a minimum, all patients over 65 years in age should be screened for frailty in primary care using the CFS, and comorbidities should be documented in referral letters. Correspondence should describe the severity of comorbidities (including cognitive impairment), how they are managed, nutritional status, and a detailed social and functional history. Surgical referrals should prompt hospital frailty specialists to coordinate perioperative optimisation of patients with a CFS ≥5 (British Geriatric Society, 2019).

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Figure 2.

Priorities in the perioperative care of frail patients.

Other chronic diseases of note

Numerous chronic diseases can impact perioperative care, too many to cover in detail in this article. Among these are several that may warrant specialist input and substantial perioperative planning:

Learning disabilities and cognitive impairment;

Nutrition

Malnourished patients lack the physiological reserve to mount an effective stress response to surgery and recovery from surgery. Malnourished patients may not be under weight, and it cannot be assumed that obese patients have a good nutritional status. Sometimes underlying pathology for which the patient is undergoing surgery can contribute to a poor nutritional state (e.g. Crohn’s disease). Hypoalbuminaemia (<30 g/L) is not a direct measure of malnutrition, but may be the best biomarker of disease severity and correlates with a poor prognosis following surgery (Matthews et al., 2021).

Although appropriate services appear more readily available to those working in secondary care and POACs, late intervention for malnutrition is likely to severely limit its impact. Primary care services should screen preoperatively for malnutrition, using a screening tool such as the Malnutrition Universal Screening Tool or Patients Association Nutrition Checklist, and be able to provide patients with information on good nutrition, including increasing protein consumption. Dietician referrals may be warranted for high-risk patients detected by screening tools. Other services worth involving on a case-by-case basis include speech and language therapy and dentists (if poor oral health and swallowing are causing malnutrition), or social services in circumstances of self-neglect (Centre for Perioperative Care and British Geriatric Society, 2021). It is important to acknowledge that optimal recovery requires nutritional management to continue throughout the recovery period, when patients return to the care of their GPs and community nurses.

Polypharmacy

This article provides numerous recommendations for optimising patients’ comorbidities using pharmacotherapy, but it is important to recognise that polypharmacy leads to more frequent perioperative adverse drug reactions in multimorbid patients. A contemporary list of medications should be supplied with referrals as certain drug groups pose particular challenges and require additional perioperative planning:

Opioid dependency and tolerance can impact on anaesthesia, pain management and immediate postoperative recovery

A general principle of dose stability ought to be applied for most drugs e.g. antihypertensive and anticoagulant medications. For other drug groups, e.g., opioids, slow preoperative weaning can be helpful (Faculty of Pain Medicine, 2021).

Referral for surgery presents an opportunity to rationalise and reduce drug prescriptions by undertaking a comprehensive medication review. The STOPP-START tool (O’Mahony, 2015) and other resources may aid decision-making, including evidence-based deprescribing algorithms for proton pump inhibitors (PPIs), hypoglycaemics and antipsychotics, recommended by the British Geriatric Society (Deprescribing.org, 2022).

Exercise prehabilitation

Irrespective of body habitus, poor aerobic fitness is associated with a higher incidence of post-operative complications, longer hospital admissions, and slower recovery. All patients scheduled for surgery benefit from being reasonably physically fit, and fitness can be markedly improved within 2 to 3 weeks. Although physical activity is important for long-term health outcomes, there is limited evidence for its benefit in preparation for surgery unless it involves regular periods of aerobic exercise (Moonesinge et al., 2021). This is yet another example of how referral for surgery may prompt physically inactive patients to make radical lifestyle changes to improve their chance of a good postoperative recovery.

In the primary care setting, a detailed social history will reveal qualitative information about a patient’s ability to perform activities requiring sustained aerobic metabolism. However, it is widely recognised that clinicians estimate functional capacity very poorly. Therefore, Duke’s Activity Status Index (DASI), a simple validated tool, is widely employed in the POAC setting to screen for poor physical fitness and can be used by GPs. Identifying patients with a DASI score of ≤34, and therefore a significant increased risk of perioperative cardiac events can help target resources.

Extraordinary measures are rarely required to improve physical fitness, and recommendations fall in line with national guidance ( Box 1). Patients should follow exercise routines that incorporate moderate to vigorous intensity interval training (Table 2), as these are most beneficial to aerobic fitness. Some studies report over 90% compliance with supervised pre-operative exercise sessions; however, other studies report mixed adherence rates when exercise interventions are home-based or unsupervised (Levett and Grimmett, 2019). Therefore, support for very unfit patients or those with functional impairments or disability may need to involve exercise referral schemes and programmes with tailored modifications. When regular exercise is being introduced, the setting of targets below the recommended levels of activity can enable positive behavioural changes without discouraging patients, before efforts are escalated. Patients who keep diaries and choose their preferred type of exercise are typically more motivated. Primary care services can help patients identify any barriers to successfully meeting targets (Moonesinge et al., 2021). Box 1.

UK Chief Medical Officers’ physical activity recommendations for adults.

Patients should aim to build up to:

• Minimum 75 minutes vigorous physical activity or 150 minutes moderate activity per week, spread over the week

• Whole-body strength and resistance exercise twice per week using weights or resistance bands

• Balance and flexibility exercise twice per week e.g., yoga

Source: Department of Health and Social Care (2019).

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Table 2.

An example for self-monitoring exercise intensity.

	Low intensity	Moderate intensity	Vigorous intensity
Breathing	Easy to breathe	Breathing more heavily	Breathing very hard
Speech	Speaking comfortably	Complete one to two sentences	Broken sentences only
Heart rate (estimated max. HR = 220-age)	Under 55% maximum HR	55–75% max. HR	Over 75% max. HR
Example exercise	Slow walk	Brisk walkCycle 10 mphGeneral gardeningDancing	RunningCycle faster than 10 mphHeavy gardeningSwimming front crawl

Source: From Preoperative Assessment and Optimisation for Adult Surgery (2021) (Moonesinge et al., 2021).

Patients undergoing procedures in specialist centres (e.g. for cardiac and cancer surgery) may have access to specific exercise prehabilitation programmes. However, the broader implementation of exercise prehabilitation remains in its infancy with limited evidence for improved surgical outcomes (Sandhu and Akowuah, 2019). Multidisciplinary services with a much broader scope of practice that integrate primary and secondary care, are worthy of further research. Meanwhile, in the perioperative setting, efforts should focus on achieving the simple exercise goals already discussed.

Shared decision-making and treatment escalation planning

Promoting patient autonomy by means of shared decision-making is a core principle of perioperative care. Primary and secondary care providers have a role in planning diagnostic tests, considering management options and referral for surgery, making positive lifestyle changes and supporting patient education and psychological welfare.

Patients should be involved in frank discussions about their suitability for surgery and wishes for treatment escalation if there are significant risks of intraoperative and postoperative complications, including long-term disability and death (Hall et al., 2019). GPs should support their patients’ psychological preparation for surgery, including discussing the likely impact of surgery on their social situation (e.g. work, caring responsibilities, and functional independence). The Fitter, Better, Sooner toolkit should be openly advertised to patients preparing for surgery (Swales et al., 2020).

For treatment escalation planning, surgery presents a specific challenge as the perioperative period carries a risk of precipitating cardiac arrest. GPs who proactively engage with patients on issues relating to treatment escalation during times of good health can ensure that patients’ wishes are known in advance of surgery (Coulter and Collins, 2011).