Validation of preoperative cardiopulmonary exercise testing-derived variables to predict in-hospital morbidity after major colorectal surgery.
British Journal of Surgery. West MA, Asher R et al. 2017;103: 744–752
Presented by Dr L. Emmett
Background
- Major colorectal surgery carries substantial morbidity and mortality – 30 day mortality of 2.9%
- Risk stratification permits collaborative decision making, optimisation and effective utilisation of hospital resources
- CPET is an objective measure of physical fitness under stress, mimicking surgery
- This study aimed to assess the predictive value of selected CPET variables and their association with in-hospital morbidity in major elective colorectal surgery
Methods
- 6 UK hospitals recruited consecutive adult patients over a 3 year period
Inclusion criteria
- Major elective colorectal surgery
Exclusion criteria
- Emergency surgery
- Neoadjuvant chemotherapy
- Lower limb dysfunction
- Inability to consent
- Inflammatory bowel disease
- Distant metastases
- CPET was conducted according to American Thoracic Society and American College of Chest Physician guidelines
- Standard protocols used for all patients – observations recorded were heart rate, 12 lead ECG, blood pressure and pulse oximetry. Ventilation and gas exchange were monitored using a metabolic cart
- In-hospital morbidity was measured at 5 days post op using an objective scoring system, Dindo score and post op 30 day mortality were also recorded
Primary aim
- Compare the postoperative morbidity score and the V02 at lactate threshold and peak exercise
Secondary aims
- To compare multi variable relationship between patient demographics, CPET variables and post operative in hospital morbidity
Intervention
- Statistical analysis of CPET variables matched with POMS tool
- 425 patients to be recruited to demonstrate that these variables were better than chance at risk prediction
Results
- 7% had postoperative complications
- VO2 lactate threshold <11.1ml/kg/min and VO2 peak threshold <18.2ml/kg/min were associated with a statistically significant increase in post operative complications
- BMI >27 and open procedures (rather than laparoscopic) associated with increased complications
Conclusions
- There was a statistically significant increase in postoperative morbidity in those patients with a lower VO2 at lactate threshold, VO2 at peak, and O2 pulse at lactate threshold
Strengths
- Conclusion matches primary aim
- More evidence that CPET testing is valuable, potentially selecting appropriate patients and risk stratifying
- Potential for increasing CPET provision, funding and awareness
- No adverse effects
- Strong statistical significant observed
- In keeping with findings from other studies
Weaknesses
- No new knowledge, only backing up existing evidence
- Unblinded study, CPET data used in clinical management
- Centre to centre variations in findings
- CPET isn’t the whole story!
Implications and Potential for Impact
- Further increasing evidence base
- Increase provision of CPET services
- Stimulate further research in high risk patients
- Asks questions about utilisation with other risk scoring systems
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