Personalised Prehabilitation in High-risk Patients Undergoing Elective Major Abdominal Surgery. A Randomised Blinded Controlled Trial.
Annals of Surgery 2018;267(1):50-56 doi:10.1097/SLA.0000000000002293
Presented by: Rebeca Harris ST4
Background
- Major abdominal surgery is associated with a high rate of postoperative complications, particularly in elderly patients with multiple comorbidities.
- Aerobic capacity determines postoperative functional reserve, which is negatively associated with postoperative morbidity and mortality.
- Prehabilitation exercise programmes are postulated to improve aerobic capacity, and thereby reduce postoperative complications.
- Previous studies have shown a bias towards low-risk patients, and lack of evidence on postoperative clinical outcomes.
- Prehabilitation is defined as a preparatory intervention aiming to increase aerobic capacity. Methods include supervised endurance exercise training and the promotion of physical activity.
Design & Setting
- Single centre: Hospital Clinic de Barcelona
- Patients were blindly randomized
- Collaborating anaesthetists and surgeons were blinded to patient’s allocation
- Ethics approved
- Sample size prospectively powered (as standard, accepting risks of: α 0.05 and β 0.2), based on:
- the reduction rate of patients with postoperative complications as the main outcome
- considering the local colorectal complication rate (30%), and
- anticipating up to 20% drop out
- Intention-to-treat analysis
Subjects
High risk patients for elective major abdominal surgery
Inclusion criteria:
- Elective major abdominal surgery
- High risk defined by all of the following:
- Age > 70 and/or ASA III/IV
- Duke Activity Status Index Score < 46
- Preop schedule allowed at least 4 weeks for the prehabilitation intervention
Exclusion criteria:
- Non-elective surgery
- Unstable cardiorespiratory disease
- Locomotor limitations precluding exercise training
- Cognitive deterioration impeding adherence to the programme
Intervention
- Baseline assessment within 1 week of preoperative assessment
- Reassessment 1 week before surgery
Standard care:
- Physical activity, nutritional and smoking cessation advice
- IV iron if indicated for anaemia
- Nutritional intervention if high-risk for malnutrition
Intervention:
- Personalised prehabilitation programme based on health and social circumstances
- Mostly community based
- 3 major aspects
- Motivational interview to assess adherence profile. Tailored physical activity programme then co-designed with the patient
- Personalised daily physical activity programme
- Pedometer to measure steps, then feedback and optimization
- Supervised high intensity endurance exercise programme
- 1-3 per week
- Exercise bike interval training, tailored to increase intensity over time, based on work rate
- Pulse oximetry and self-perceived exertion measured
Outcomes
Primary
- Number of patients with a complication
Secondary
- Number and severity of postoperative complications
- Hospital and ICU length of stay
Other
- Endurance time
- Distance covered in 6 minute walking test
- Physical activity (by validated patient survey)
- Self perceived health status (by validated patient survey)
- Psychological status (by HADS patient survey)
- Pulmonary function tests
- Cardiorespiratory exercise tests
Results
Baseline characteristics
- 209 assessed over 3 years – 144 eligible and randomised (> 70 per group, as per power analysis minimum)
- Comparable patient characteristics between groups
- 19 did not receive operation, so excluded mid-trial
- Control: 1 unable to perform exercise testing, 6 abandoned
- Intervention: 4 unable to perform exercise testing, 4 abandoned
- 56 (Control) and 54 (Intervention) completed trial (< 70 per group, and > 20% dropout rate, thus underpowered)
Control
- No change in baseline characteristics at start vs 1 week pre-surgery
Prehabilitation intervention
- Mean duration 6 weeks + 12 supervised exercise session
- PRMIARY OUTCOME
- 50% reduction in number of patients with complications: 31% vs 62%, RR 0.5 (95% CI 0.3-0.8), p = 0.001
- SECONDARY OUTCOMES:
- Increasein Endurance Time (135%, p < 0.001)
- Increasein Physical Activity Index (37 points, p< 0.001)
- No significant difference in intraoperative parameters, but trend towards lower requirement of vasoactive drugs (p=0.053)
- Lower mean number of complications per patient : Cardiovascular(p = 0.03, RR 0.1, 95% CI 0.1-1.0), Infection of uncertain source (p = 0.013, RR not possible), Paralytic ileus (p = 0.001, RR not possible)
- In patients with complications, intervention reducedrisk of having more than one complication (RR 0.6, but 95% CI 0.3-1.1), but no effect on severity of complications.
- Reduced length of ICU stay (3 vs 12 days, p = 0.046)
Conclusions
- High intensity endurance exercise training is feasible and safe in elderly and/or multimorbid candidates for major abdominal surgery
- Prehabilitation enhanced clinical outcomes in high-risk candidates for elective major abdominal surgery, which can be explained by the increase in aerobic capacity
- Reduced complication rate
- Prevents > 1 complication
- Reduced ICU length of stay
Strengths
- Randomised blinded controlled trial
- High risk patient group selected, reflecting patient population
- Initially adequately powered
- Performed within realistic preoperative timeframe for urgent surgery
- Highly personalised, patient-centred prehabilitation programme. Well detailed for reproducibility
- Interesting secondary outcomes, validated tools used
- Appropriate statistical analysis employed
- Number of patients abandoning intervention arm < control, thus patient engagement good
Weaknesses
- Single centre
- Blinding of clinicians following interaction with patients may have been difficult
- Underpowered following dropouts – still able to demonstrate statistically significant difference in primary outcome, however may have ‘missed’ other significant differences in secondary outcomes
- ? Blinding of exercise tester
- Primary outcome extremely broad – ‘any complications’ postoperatively. Not specific, and therefore clinical significance and importance of question reduced.
- Survival and functional recovery not assessed
- Underpowered to assess effect on specific and important post operative complications
- Did not demonstrate a difference in the severity of postoperative complications
- Claims significant reduction in CV complications and the number of patients having > 1 complication, but:
- Reduction in CV complications 95% CI 0.1-1, wide and includes ‘no effect’
- Reduction in number of patients having more than 1 complication 95% CI 0.3-1.1, wide and includes ‘no effect’
- Endurance time rather than familiar, objective CPEX data e.g. Anabolic threshold, formed basis of measure of aerobic capacity
- Intensive, highly tailored programme
- ? Sustainability on larger scale
- No cost analysis
Implications
- Prehabilitation in elderly, multimorbid patients appears to be feasible, safe and ‘acceptable’ to patients
- Prehabilitation can increase preoperative exercise endurance in high risk patients
- Postoperative complication rates can be reduced by this strategy
- However, larger trials are required to further characterise and assess the clinical significance of postoperative complication benefits, and to determine the effect on functional recovery and survival
Potential for impact
- Important step towards assessing the potential benefits and characterising the design of prehabilitation exercise programmes in high risk patients undergoing high risk elective surgery
- Important and exciting emerging field of research with potential for significantly improving patient outcomes
Leave a Reply