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Mawston G1, McNair P1, Whyte I2, Bigwood B3, Sangamnerkar G3, Harrison I3
1AUT University, Department of Physiotherapy, Health and Rehabilitation Research Institute, Auckland, New Zealand, 2South Canterbury DHB, Department of Anaesthesia, Timaru, New Zealand, 3Waitemata District Health Board, Department of Anaesthesia, Auckland, New Zealand
Background: Aerobic fitness (peak oxygen consumption (VO2) and anaerobic threshold (AT)) is an important measure for risk stratification and exercise prescription in cancer patients undergoing major abdominal surgery. Currently, most clinical testing of this patient group is performed under medical supervision and requires a high level of expertise and expensive equipment. Submaximal predicted tests of aerobic capacity using heart rate measures are limited for this group because a number of these individuals take heart rate altering medication. The development of a sub-maximal exercise test using workload and perceived exertion may provide clinicians with a simple tool to estimate aerobic fitness in this group.
Purpose: To determine whether sub-maximal ratings of perceived exertion (RPE) elicited during a graded exercise test could provide an estimate of aerobic fitness in abdominal cancer sufferers, taking heart rate altering medication, who were considered for major abdominal surgery.
Methods: Fourteen participants with abdominal cancer (mean age=75 years) who were medicated with beta-blockers were age-matched to a similar group of cancer patients who were not medicated with beta-blockers . All participants were undergoing clinical cardiopulmonary exercise testing (CPET) for risk stratification prior to major abdominal surgery, which involved a 15 Watt per minute ramped cycle exercise protocol to exhaustion. Breath by breath gas analysis was used to determine AT (v-slope method) and VO2 peak. RPE was recorded every minute throughout the test. T-Tests were used to determine differences between groups for AT, VO2 peak, RPE and heart rate measures. Regression analysis was performed between workload at an RPE of 13 and actual VO2 peak. The equation developed from regression was then used to calculate predicted VO2 peak for each participant. Intraclass correlation coefficients were then calculated for the predicted vs actual VO2 peak.
Results: The beta-blocker group displayed significantly lower heart rates at AT and VO2 peak than the control group (P 0.05). However, VO2 and workload at AT and peak exercise did not differ between groups. Workload at an RPE of 13 and workload at AT were not significantly different for either group. Workload per kg at an RPE of 13 (somewhat hard) was a good predictor (R2 = 0.67) of VO2 peak, with the intraclass correlation between VO2 peak predicted by the regression equation and actual VO2 peak being 0.82.
Conclusion(s): Workload attained at an RPE of 13 during a graded exercise test provided an accurate measure of aerobic fitness in patients with abdominal cancer taking beta-blocker medication.
Implications: A simple low-cost incremental submaximal cycle ergometer test up to an RPE of 13 (somewhat hard) has the potential to be used by physiotherapist to estimate VO2 peak in abdominal cancer patients taking beta-blockers. Furthermore, a RPE of 13 is indicative of AT, and could be used as a training parameter for this patient group.
Keywords: Abdominal cancer, aerobic fitness, ratings of perceived exertion
Funding acknowledgements: AUT PBRF funding.
Purpose: To determine whether sub-maximal ratings of perceived exertion (RPE) elicited during a graded exercise test could provide an estimate of aerobic fitness in abdominal cancer sufferers, taking heart rate altering medication, who were considered for major abdominal surgery.
Methods: Fourteen participants with abdominal cancer (mean age=75 years) who were medicated with beta-blockers were age-matched to a similar group of cancer patients who were not medicated with beta-blockers . All participants were undergoing clinical cardiopulmonary exercise testing (CPET) for risk stratification prior to major abdominal surgery, which involved a 15 Watt per minute ramped cycle exercise protocol to exhaustion. Breath by breath gas analysis was used to determine AT (v-slope method) and VO2 peak. RPE was recorded every minute throughout the test. T-Tests were used to determine differences between groups for AT, VO2 peak, RPE and heart rate measures. Regression analysis was performed between workload at an RPE of 13 and actual VO2 peak. The equation developed from regression was then used to calculate predicted VO2 peak for each participant. Intraclass correlation coefficients were then calculated for the predicted vs actual VO2 peak.
Results: The beta-blocker group displayed significantly lower heart rates at AT and VO2 peak than the control group (P 0.05). However, VO2 and workload at AT and peak exercise did not differ between groups. Workload at an RPE of 13 and workload at AT were not significantly different for either group. Workload per kg at an RPE of 13 (somewhat hard) was a good predictor (R2 = 0.67) of VO2 peak, with the intraclass correlation between VO2 peak predicted by the regression equation and actual VO2 peak being 0.82.
Conclusion(s): Workload attained at an RPE of 13 during a graded exercise test provided an accurate measure of aerobic fitness in patients with abdominal cancer taking beta-blocker medication.
Implications: A simple low-cost incremental submaximal cycle ergometer test up to an RPE of 13 (somewhat hard) has the potential to be used by physiotherapist to estimate VO2 peak in abdominal cancer patients taking beta-blockers. Furthermore, a RPE of 13 is indicative of AT, and could be used as a training parameter for this patient group.
Keywords: Abdominal cancer, aerobic fitness, ratings of perceived exertion
Funding acknowledgements: AUT PBRF funding.
Topic: Oncology, HIV & palliative care; Cardiorespiratory
Ethics approval required: Yes
Institution: Waitemata District Health Board
Ethics committee: Clinical Audit
Ethics number: 980712535
All authors, affiliations and abstracts have been published as submitted.
