The elements of a prehabilitation programme

In this second article on prehabilitation, Dr Dan Bendel explains the key elements of a prehabilitation programme and how they fit together.

Prehabilitation physiology: training for a marathon!

The surgical stress response precipitates an increase in oxygen consumption, metabolic rate, protein catabolism, and a negative nitrogen balance. The severity of this catabolic response rises in proportion to the extent of surgical trauma, and depends on inter-patient variations in immune and neuro-endocrine responses. This is then exacerbated by a period of physical inactivity and reduced nutritional intake in the postoperative phase. A secondary decline in functional capacity is therefore precipitated, rendering a patient even more vulnerable to complications.

With aerobic fitness training however, a patient’s ability to mount a cardiorespiratory response to physiological stress improves, with an increase in cardiac output, arteriovenous oxygen concentration, muscle mass and the oxygen-carrying capacity of skeletal muscle. As described in the CPET chapter, this is evident on repeated exercise testing.

Optimising cardiorespiratory fitness through exercise is impactful, but it must with done in combination with sufficient nutritional and psychological interventions in order to achieve the best outcomes. Furthermore, medical input from specialists in gerontology and internal medicine ensure medical optimisation. Lifestyle modifications such as smoking and alcohol cessation play a significant role here too.

In this way, prehabilitation aims to ameliorate the effects of the inflammatory response to surgery by better enabling a patient to meet the increased metabolic demands of surgery in the postoperative period. Complications are better prevented, with a more likely return to functional baseline later on. These concepts are summarised in the image below (Figure 2).

Figure 2: The prehabilitation concept (taken from Whittle et al, 2018)

Prehabilitation: Service design

Patients who are able to mount an adaptive response to surgical stress reduce the risk of postoperative complications [1]. As we have seen, this adaptive response results from a multiplicity of modifiable factors.

Prehabilitation is therefore a multidisciplinary, multimodal approach, consisting of a preoperative programme of medical optimisation, lifestyle modification, exercise training and nutritional and psychological support [2].

It’s component parts are summarised in Figure 3.

Figure 3: The prehabilitation model (taken from Durrand et al, 2017)

Carry onto our final step on prehabilitation, where you will hear from Dr John Whittle about his experiences of setting up a prehab service in UCLH.

References

1. Whittle J, Wischmeyer PE, Grocott MPW, Miller TE. Surgical Prehabilitation. Anesthesiol Clin. 2018 Dec;36(4):567–80.
2. Durrand J, Singh SJ, Danjoux G. Prehabilitation. Vol. 17, Clinical Medicine. 2017.