The curriculum asks us to 'Describe strategies for prehabilitation and patient optimisation and the limits of such strategies'.
Prehabilitation was the subject of an SAQ in March 2019 (71% pass rate); candidates gave poor answers on 'basic sciences...[and] the benefits of carbohydrate preloading'.
The overall risk of death and major complications from surgery is low (<2%)
However, poorer outcomes are seen in patients with impaired pre-operative functional capacity
Typically includes the elderly, the frail or the multiply co-morbid patient
These higher-risk patients represent 12.5% of the surgical population, but account for 80% of post-operative deaths
Although there is no consistent or widely-accepted definition of prehabilitation (BJA, 2024), it can be thought of as:
The practice of enhancing a patient's pre-operative functional capacity, with the aim of improving post-operative outcomes
Major surgery causes a host of physiological responses, including:
A catabolic state
Systemic pro-inflammatory response including metabolic dysregulation
Muscle inflammation and mitochondrial dysfunction
The interventions which form prehabilitation aim to place the patient in a better state to withstand this insult and any post-operative complications which arise
Benefits of prehabilitation
Associated effects of prehabilitation programmes
↓ length of hospital stay
↓ length of critical care stay
↓ complication rate
↓ frailty scores
↑ QoL
↓ 1yr mortality
↑ disability-free survival
Constituent elements of prehabilitation
Programmes target their intervention during the 'teachable moment' period between deciding to proceed with surgery, and surgery itself
Most programmes are 4 - 8 weeks in duration, balancing effectiveness (reduced in shorter programmes) and compliance (reduced in longer programmes)
Prehabilitation programmes utilise an MDT to improve functionality via:
Medical optimisation
Physical exercise
Nutritional support
Psychological support
Smoking cessation
Smoking is associated with a variety of adverse perioperative outcomes
Cessation may lead to:
↓ Cardiovascular complications
↓ Wound infections
Better wound healing and bone fusion
↓ Length of stay
↓ Mortality
Weight loss
The greatest risk of major post-operative complications occurs in the underweight patient
Obese patients tend to have higher rates of wound infections, blood loss and longer durations of surgery than normal weight patients
The obesity paradox, however, is that obese patients have better 30-day and long-term survival
Alcohol misuse
There is a dose-dependent increase in post-operative morbidity with alcohol consumption
Complications associated with excess alcohol consumption include immunosuppression, exaggerated stress response, cardiac insufficiency and haemostatic imbalance
4 weeks of pre-operative abstinence can reduce perioperative morbidity
Other elements
Optimisation of a host of commonly occurring medical comorbidities associated with poor perioperative outcomes such as:
Repeat testing at the end of the programme may occur, to quantify changes in functional capacity
Exercise regimens
Appreciable muscle growth often cannot be achieved in the short timeframes available, but improved aerobic capacity and metabolic flexibility are possible
The optimal exercise regimen has not been defined, with existing programmes consisting of various:
Types of exercises, typically a blend of aerobic exercise and resistance training, although some include other aspects such as inspiratory muscle training, stretching or HIIT
Durations, from 2 weeks to 12 weeks
Frequency of sessions, from 1 to 5 sessions per week
Location, either more intense professionally supervised in-hospital sessions or home-based exercises
The Borg scale is a subjective rating scale of perceived exertion during exercise
It runs from 6 (no exertion at all) to 20 (maximal exertion)
Exercise intensity in prehabilitation programmes targets a Borg intensity of 12 - 16
The improvement in performance required to result in an improvement in surgical outcome is not known
The impact on long-term outcomes is unknown
Adverse nutritional status is associated with poor post-operative outcomes, such as:
Infectious complications
Length of stay
Readmission rate
Mortality
Formal screening of nutrition should take place before any major surgery
If found to be at risk or malnourished, patients should be referred to a dietician for nutritional assessment
Interventions
Malnourished patients should receive up to 10-14 days of enteral nutritional support, including:
Carbohydrate loading pre-operatively
1.5g/kg IBW protein to limit nitrogen losses e.g. high protein oral nutritional supplements with fortisip, fortijuice
Glutamine, arginine, omega-3 fatty acids and nucleotides (so-called 'immune-modulating nutrition')
May reduce hyperinflammation caused by the surgical stress response
It should be commenced 5-7 days pre-operatively and continued post-operatively
Outcomes
Evidence suggests:
Targeted nutritional therapy can reduce post-operative complications
Immune-modulating nutrition can reduce post-operative complications and length of stay
Nutritional prehabilitation, either alone or combined with other aspects of prehabilitation, can reduce length of stay
Psychological stressors and the fear of surgery produce immunological dysregulation
This contributes to post-operative pain, complications inc. wound healing and delayed recovery
Psychological support strategies aim to:
Reduce psychological distress/anxiety associated with diagnosis & surgery
Maximise motivation and empower patients to comply with other parts of the programme
Screening
Screening include the HADS (Hospital anxiety and depression score)
Separate scores for depression and anxiety
Scores:
<7 = normal
8 - 10 = borderline
>11 = case of depression/anxiety
Interventions
Providing sensory information i.e. what the perioperative experience will feel like
Cognitive behavioural therapy
Relaxation techniques
Emotion-focused interventions
Mindfulness-based interventions
Coping strategies
Hypnosis
Provision of procedural information i.e. details of the patient journey
Such interventions may reduce post-operative anxiety and pain, although have not been shown to reduce morbidity, mortality or length of hospital stay
May only be as effective as rehabilitation
Prehabilitation increases functional capacity to a greater extent
However no difference in complication rate, hospital length of stay, readmission rates, recovery of walking capacity or patient-reported outcomes
Evidence base suffers from:
Heterogeneity of studied populations, interventions, and outcome measures
Small sample sizes
Potential for bias from inclusion of low-risk populations
Potential for bias from inability to blind participants
This limits robust meta-analysis and the evidence base is relatively weak
Evidence for reduced rate of post-operative complications and decreased length of stay is low
No demonstrated effect on mortality
Some aspects of prehabilitation don't improve outcomes in isolation, but may do so as part of multi-modal intervention programmes (marginal gains theory)
May improve functional measures (e.g. VO2 peak, grip strength, global health status) but not clinically relevant outcomes such as morbidity, mortality, length of stay or readmission rates
Potential for adverse events from exercise interventions although this has not manifested in the literature
May not be cost-saving, although may be cost-effective up to a cost of $9,500/patient